Interfacial electron accumulation for efficient homo-junction perovskite solar cells

Song, Seulki,Moon, Byung Joon,Hö,rantner, Maximilian T.,Lim, Jongchul,Kang, Gyeongho,Park, Min,Kim, Jin Young,Snaith, Henry J.,Park, Taiho Elsevier 2016 Nano energy Vol.28 No.-

<P><B>Abstract</B></P> <P>Here we study perovskite solar cells based on mesoporous alumina scaffold infiltrated and capped with a perovskite absorber layer, which are devoid of a discrete n-type electron collection layer. We employ ethoxylated polyethylenimine (PEIE) to modify the interface between the perovskite absorber layer and the metallic transparent fluorine-doped SnO<SUB>2</SUB> (FTO) electrode. Surprisingly, the PEIE interlayer obviates the requirement for the conventional dense-TiO<SUB>2</SUB> (d-TiO<SUB>2</SUB>) compact layer (or organic fullerene layer), usually required to selectively extract electrons from the perovskite film. The self-organized PEIE interlayer produced a strong induced dipole moment at the perovskite-FTO interface, with our results indicating that electrons accumulate within the perovskite film at this interface. The resultant “n-type” contact region within the perovskite absorber layer, progressing to an intrinsic (i) region within the bulk of the perovskite layer, represents an n-i homojunction and favorably enables selective electron extraction at the FTO electrode. Resulting solar cells deliver current-voltage measured power conversion efficiencies (η) of over 15.0% and a substantial stabilized efficiency (η) of 9.1%. Although our solar cell performance remains lower than the highest reported efficiencies for perovskite solar cells employing discrete charge selective extraction layers, it indicates significant potential for “homo-junction” perovskite solar cells, once the metallic-to-perovskite contact is fully controlled. Additionally, our work identifies the potential impact of modifying the interface between the perovskite absorber and the subsequent contact materials with dipolar organic compounds, which may be applicable to optimizing contact at perovskite-semiconductor heterojunctions.</P> <P><B>Highlights</B></P> <P> <UL> <LI> N-type less perovskite is proposed with stabilized power output efficiency. </LI> <LI> PEIE interlayer make an induced dipole at perovskite interface. </LI> <LI> Band bending of perovskite layer induces the charge accumulation. </LI> <LI> Perovskite solar cell have a permanent built-in potential which gives a stabilized maximum power output efficiency without n-type electron selective layer. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Self-powered reduced-dimensionality perovskite photodiodes with controlled crystalline phase and improved stability

Lim, Ju Won,Wang, Huan,Choi, Chi Hun,Kwon, Hannah,Quan, Li Na,Park, Won-Tae,Noh, Yong-Young,Kim, Dong Ha Elsevier 2019 Nano energy Vol.57 No.-

<P><B>Abstract</B></P> <P>In this work, we developed the perovskite photodiodes based on the dimensionality-reduced quasi two-dimensional (Q-2D) photoactive layer structure by incorporating phenylethylammonium iodide (PEAI) into methylammonium lead iodide (MAPbI<SUB>3</SUB>), which effectively enhanced both the crystalline phase and the ambient stability of the perovskite. The Q-2D perovskite photodiode exhibited a dark current of 1.76 × 10<SUP>−7</SUP> A/cm<SUP>2</SUP>, resulting in the detectivity (D*) of 2.20 × 10<SUP>12</SUP> J and responsivity of 0.53 A/W, which is among the highest performance levels without the voltage bias (0 V) due to the systematically optimized perovskite phase resulting in the reduced leakage current. In addition, the current density of Q-2D perovskite photodiode maintained 76% of the initial level current density even after 80 days in the ambient condition, compared to 15% of 3D perovskite photodiode control sample. Such superior performance and stability were mainly attributed to the enhanced degree of crystallization of the Q-2D perovskites, which was confirmed by X-ray diffraction and grazing incidence wide-angle X-ray scattering (GIWAXS) measurement. Also, the improved stability of Q-2D perovskite films was confirmed by both lifetime test and atomic force microscopy studies where the negligible number of pinholes was observed in the quasi-2D perovskite films while considerable deformations were found in the 3D perovskites photodiode. Our study suggests a simple and robust protocol for the development of stable and high-performance perovskite photodetectors via dimensional and constitutional optimization of conventional perovskites for the practical usage of perovskite in the photodiode applications.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The Q-2D perovskite photodiode exhibited the D* of 2.20 × 10<SUP>12</SUP> J and R of 0.53 A/W without the voltage bias (0 V). </LI> <LI> The current density of Q-2D perovskite photodiode maintained 76 % of the initial level while 15 % for the 3D one. </LI> <LI> Grazing incidence wide-angle X-ray scattering (GIWAXS) analysis revealed the origin of the stability improvement. </LI> <LI> Quasi-2D perovskite materials can be promising candidates for stable, tunable and flexible optoelectronic applications. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>Dimensionality-controlled perovskite photodiodes with improved stability were systematically fabricated while retaining the comparable electrical performance of conventional three-dimensional perovskites. The quasi-2D perovskite photodetector exhibited an improved detectivity of 2.20 × 10<SUP>12</SUP> J performance and maintained 76% of initial level while the performance of three-dimensional perovskite photodetector remained only 15% after 80 days. Our study suggests a facile solution for the poor stability of the three-dimensional perovskite, with a potential for the development of highly-stable perovskite optoelectronics.</P> <P>[DISPLAY OMISSION]</P>

고효율 적층형 태양전지를 위한 유무기 페로브스카이트

박익재(Ik Jae Park),김동회(Dong Hoe Kim) 한국세라믹학회 2019 세라미스트 Vol.22 No.2

To overcome the theoretical efficiency of single-junction solar cells (> 30 %), tandem solar cells (or multi-junction solar cells) is considered as a strong nominee because of their excellent light utilization. Organic-inorganic halide perovskite has been regarded as a promising candidate material for next-generation tandem solar cell due to not only their excellent optoelectronic properties but also their bandgap-tune-ability and low-temperature processpossibility. As a result, they have been adopted either as a wide-bandgap top cell combined with narrow-bandgap silicon or CuIn x Ga (1-x) Se 2 bottom cells or for all-perovskite tandem solar cells using narrow- and wide-bandgap perovskites. To successfully transition perovskite materials from for single junction to tandem, substantial efforts need to focus on fabricating the high quality wide- and narrow-bandgap perovskite materials and semi-transparent electrode/recombination layer. In this paper, we present an overview of the current research and our outlook regarding perovskite-based tandem solar technology. Several key challenges discussed are: 1) a wide-bandgap perovskite for top-cell in multi-junction tandem solar cells; 2) a narrow-bandgap perovskite for bottom-cell in allperovskite tandem solar cells, and 3) suitable semi-transparent conducting layer for efficient electrode or recombination layer in tandem solar cells.

Improving the stability and Efficiency of carbon-based perovskite solar cells via interfacial growth of 2D perovskite

김중원,장정식 한국공업화학회 2019 한국공업화학회 연구논문 초록집 Vol.2019 No.0

In the past few years, carbon-based perovskite solar cells (PSCs) have been received tremendous attentions by their remarkable long-term stability and low-cost of material and fabrication process. However, reduced charge transport capability due to the poor interfacial contact between perovskite and carbon should be solved to fabricate a highly efficient carbon-based device. Herein we introduce an effective method for post-growth of two-dimensional (2D) perovskite layer at the interface between 3D perovskite layer and carbon-electrode. 2D perovskite layer formed within perovskite/carbon interfaces improves the poor contact of carbon-electrode and obtains optimized energy band alignment. The carbon electrode-based PSCs made with 2D perovskite layer exhibited excellent photovoltaic performances, achieving efficiency over 15%. Furthermore, the devices show superior thermal and air stability due to dual protection of 2D perovskite and carbon layer.

페로브스카이트 태양전지에 관한 고찰: 재료 및 장치적 특성

최다영,임세영,김한결 한국태양광발전학회 2023 Current Photovoltaic Research Vol.11 No.1

Tin perovskite solar cells have attracted a lot of attention due to their potential to address the toxicity of lead, which is the biggest barrier to commercialization of perovskite solar cells. Unlike other lead-free perovskite, tin perovskite have a direct bandgap, which is suitable for use as light harvesting, and relatively good stability, which has led to a lot of attention. Since the first tin perovskite solar cell was reported in 2014, it has achieved an impressive power conversion efficiency of 14.81%. However, this efficiency is still low compared to that of lead perovskite solar cells, and the stability of tin perovskite solar cells is also an issue that needs to be addressed. In this review, we will discuss the basic properties of the tin atom in comparison to the lead atom, and then discuss the crystal structure, phase transition, and basic properties of tin perovskite. We will then discuss the advantages, applications, challenges, and strategies of tin perovskite, In particular, we will focus on how to prevent the oxidation of tin, which is arguably the biggest challenge for using tin perovskite solar cells. At the end, we summarize the key factors that need to be addressed for higher efficiency and stability, emphasizing what is needed to commercialize tin perovskite solar cells.

TiO₂/RbPbI₃ halide perovskite solar cells

Jung, Mi-Hee,Rhim, Sonny H.,Moon, Dohyun North-Holland 2017 Solar Energy Materials and Solar Cells Vol. No.

<P><B>Abstract</B></P> <P>Inorganic-organic halide perovskites hold the great promise for next-generation photovoltaics due to their excellent high performance and low cost. However, major limitation for the commercialization of perovskite solar cell can be attributed to the transformation and degradation of lead halide perovskite during the exposure of environmental humidity and photon irradiation. To solve these problems, herein, we apply the one-dimensional and inorganic RbPbI<SUB>3</SUB> perovskite into the solar cell because it shows the superior stability in environmental conditions. After RbPbI<SUB>3</SUB> perovskite was applied into the solar cell with a FTO/TiO<SUB>2</SUB>/RbPbI<SUB>3</SUB>/Spiro-MeOTAD/Au configuration, the device exhibits an open circuit voltage of 0.62V, photocurrent density of 3.75mA/cm<SUP>2</SUP>, fill factor of 44.60%, and 1.04% of PCE by reverse sweeping direction. Even though the performance of RbPbI<SUB>3</SUB> device was still lower than other perovskite solar cells, this approach enabled us to establish the key step to make a highly stable perovskite film, leading to the best photovoltaic performance for real applications.</P> <P><B>Highlights</B></P> <P> <UL> <LI> We applied the RbPbI<SUB>3</SUB> to a solar cell to determine the performance of 1D perovskite. </LI> <LI> RbPbI<SUB>3</SUB> perovskite shows the superior stability for the environmental conditions. </LI> <LI> The band gap alignment of RbPbI<SUB>3</SUB> perovskite is well matched with that of TiO<SUB>2</SUB>. </LI> <LI> The device with RbPbI<SUB>3</SUB> perovskite shows little hysteresis in the <I>J</I>-V scan direction. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>The solar cell was fabricated with one dimensional RbPbI<SUB>3</SUB> perovskite as a light absorber.</P> <P>[DISPLAY OMISSION]</P>

Photovoltaic Effect of 2D Homologous Perovskites

Pergamon Press 2017 Electrochimica Acta Vol. No.

<P><B>Abstract</B></P> <P>The controlled growth of mixed dimensional perovskite structures, (C<SUB>6</SUB>H<SUB>5</SUB>CH<SUB>2</SUB>NH<SUB>2</SUB>)(CH<SUB>3</SUB>NH<SUB>3</SUB>)<SUB>n-1</SUB>Pb<SUB>n</SUB>I<SUB>3n+1</SUB>, through the introduction of CH<SUB>3</SUB>NH<SUB>3</SUB>I molecule vapor into the two-dimensional perovskite C<SUB>6</SUB>H<SUB>5</SUB>CH<SUB>2</SUB>NH<SUB>3</SUB>PbI<SUB>4</SUB> structure and its application in photovoltaic devices is reported. The dimensionality of (C<SUB>6</SUB>H<SUB>5</SUB>CH<SUB>2</SUB>NH<SUB>2</SUB>)(CH<SUB>3</SUB>NH<SUB>3</SUB>)<SUB>n-1</SUB>Pb<SUB>n</SUB>I<SUB>3n+1</SUB> is controlled using the exposure time to the CH<SUB>3</SUB>NH<SUB>3</SUB>I vapor on the C<SUB>6</SUB>H<SUB>5</SUB>CH<SUB>2</SUB>NH<SUB>3</SUB>PbI<SUB>4</SUB> perovskite film. As the stacking of the lead iodide lattice increases, the crystallographic planes of the inorganic perovskite compound exhibit vertical growth in order to facilitate efficient charge transport. Furthermore, the devices have a smaller band gap, which offers broader absorption and the potential to increase the photocurrent density in the solar cell. As a result, the photovoltaic device based on the (C<SUB>6</SUB>H<SUB>5</SUB>CH<SUB>2</SUB>NH<SUB>2</SUB>)(CH<SUB>3</SUB>NH<SUB>3</SUB>)<SUB>n-1</SUB>Pb<SUB>n</SUB>I<SUB>3n+1</SUB> perovskite exhibits a power conversion efficiency of 5.43% with a short circuit current density of 14.49mAcm<SUP>−2</SUP>, an open circuit voltage of 0.85V, and a fill factor of 44.30 for the best power conversion efficiency under AM 1.5G solar irradiation (100mWcm<SUP>−2</SUP>), which is significantly higher than the 0.34% of the pure two-dimensional BAPbI<SUB>4</SUB> perovskite-based solar cell.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The mixed perovskite was prepared by exposure of MAI gas on the BAPbI<SUB>4</SUB> film. </LI> <LI> The increased dimensional perovskite shows a smaller band gap than 2D perovskite. </LI> <LI> The mixed perovskite system shows the vertical crystal orientation. </LI> <LI> The mixed perovskite cell exhibits the higher Jsc and FF than 2D perovskite cell. </LI> </UL> </P>

Fuel-Borne Catalyst와 Perovskite로 구성된 복합촉매 시스템에 의한 디젤 탄소입자상 물질의 연소반응: 반응성능과 Perovskite 촉매조성 (La_1-x A′_xBO₃: A′ = K, Sr; 0 ≤ x ≤ 1; B = Fe, Cr, Mn)의 상관관계

이대원 ( Dae-won Lee ),성주영 ( Ju Young Sung ),이관영 ( Kwan-young Lee ) 한국화학공학회 2018 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.56 No.2

최근 선진국을 중심으로 고연비-저배출 내연기관 (디젤) 자동차 보급의 필요성이 대두되면서 기존 촉매후처리 장치의 저온성능 강화를 위한 기술적 방안들이 시급히 요구되고 있다. 본 논문에서는 디젤엔진 배출 탄소입자상 물질의 연소반응에 있어 연료함유 촉매(Fuel-Borne Catalyst)와 페로브스카이트(Perovskite)의 복합촉매 시스템이 보이는 상용모델촉매 대비 우수한 저온 연소성능과 이의 Perovskite 촉매 조성에 대한 의존성에 관해 논하였다. Fe/Ce 계열 연료함유 촉매가 A-site 원소(La)에 K이 부분치환되고, B-site 금속이 Fe인 Perovskite 촉매와 복합화될 때 상대적으로 우수한 저온 연소성능 개선효과가 관찰되었다. 이를 관찰하기 위해 연료함유 촉매가 함유되거나 함유하지 않은 탄소 입자상 물질과 다양한 조성의 La 계열 Perovskite 촉매를 혼합한 고정층에 대한 온도상승 산화반응 실험(Temperature-Programmed Oxidation)을 수행하였으며, 이산화탄소 생성과 질소산화물 농도 저하 패턴의 연동특성을 통해 두 촉매의 상호 연계작용을 유추하였다. As the internal combustion engine vehicles of high fuel efficiency and low emission are demanded, it becomes important to procure technologies for improving low-temperature performance of automotive catalyst systems. In this study, we showed that the combustion rate of diesel particulate matter is greatly enhanced at low temperature by applying fuel-borne catalyst and perovskite catalyst concurrently. It was tried to examine the correlation between elemental composition of perovskite catalyst and combustion activity of mixed catalyst system. To achieve this goal, we applied temperature-programmed oxidation technique in testing the combustion behavior of perovskite-mixed particulate matter bed which contained the element of fuel-borne catalyst or not. We tried to explain the synergetic action of two catalyst components by comparing the trends of concentrations of carbon dioxide and nitrogen oxide in temperature-programmed oxidation results.

Device design rules and operation principles of high-power perovskite solar cells for indoor applications

Ann, Myung Hyun,Kim, Jincheol,Kim, Moonyong,Alosaimi, Ghaida,Kim, Dohyung,Ha, Na Young,Seidel, Jan,Park, Nochang,Yun, Jae Sung,Kim, Jong H. Elsevier 2020 Nano energy Vol.68 No.-

<P><B>Abstract</B></P> <P>In this work, we report on the design principles of high-power perovskite solar cells (PSCs) for low-intensity indoor light applications, with a particular focus on the electron transport layers (ETLs). It was found that the mechanism of power generation of PSCs under low-intensity LED and halogen lights is surprisingly different compared to the 1 Sun standard test condition (STC). Although a higher power conversion efficiency (PCE) was obtained from the PSC based on mesoporous-TiO<SUB>2</SUB> (m-TiO<SUB>2</SUB>) under STC, compared to the compact-TiO<SUB>2</SUB> (c-TiO<SUB>2</SUB>) PSC, c-TiO<SUB>2</SUB> PSCs generated higher power than m-TiO<SUB>2</SUB> PSCs under low-intensity (200–1600 Lux) conditions. This result indicates that high PCE at STC cannot guarantee a reliable high-power output of PSCs under low-intensity conditions. Based on the systemic characterization of the ideality factor, charge recombination, trap density, and charge-separation, it was revealed that interfacial charge traps or defects at the electron transport layer/perovskite have a critical impact on the resulting power density of PSC under weak light conditions. Based on Suns-<I>V</I> <SUB>OC</SUB> measurements with local ideality factor analyses, it was proved that the trap states cause non-ideal behavior of PSCs under low-intensity light conditions. This is due to the additional trap states that are present at the m-TiO<SUB>2</SUB>/perovskite interface, as confirmed by trap-density measurements. Based on Kelvin probe force microscopy (KPFM) measurements, it was confirmed that these traps prohibit efficient charge separation at the perovskite grain boundaries when the light intensity is weak. According to these observations, it is suggested that for the fabrication of high-power PSCs under low-intensity indoor light, the interface trap density should be lower than the excess carrier density to fill the traps at the perovskite's grain boundaries. Finally, using the suggested principle, we succeeded in demonstrating high-performance PSCs by employing an organic ETL, yielding maximum power densities up to 12.36 (56.43), 28.03 (100.97), 63.79 (187.67), and 147.74 (376.85) <I>μ</I>W/cm<SUP>2</SUP> under 200, 400, 800, and 1600 Lux LED (halogen) illumination which are among the highest values for indoor low-intensity-light solar cells.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The device design principles of high-power perovskite solar cells for indoor light applications were investigated. </LI> <LI> For high-power under indoor light, trap density should be lower than excess carrier density. </LI> <LI> Perovskite solar cells with high-power density up to 376.85 <I>μ</I>W/cm2 under indoor light were demonstrated. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>In this work, the device design rules for achieving high-power perovskite solar cells under indoor light are suggested based on the device operation principle under low intensity light conditions.</P> <P>[DISPLAY OMISSION]</P>

Highly efficient metal halide substituted CH₃NH₃I(PbI₂)_1−X(CuBr₂)_X planar perovskite solar cells

Jahandar, Muhammad,Heo, Jin Hyuck,Song, Chang Eun,Kong, Ki-Jeong,Shin, Won Suk,Lee, Jong-Cheol,Im, Sang Hyuk,Moon, Sang-Jin Elsevier 2016 Nano energy Vol.27 No.-

<P><B>Abstract</B></P> <P>By substitution of some part of PbI<SUB>2</SUB> to CuBr<SUB>2</SUB> in CH<SUB>3</SUB>NH<SUB>3</SUB>PbI<SUB>3</SUB> perovskite film, we fabricated inverted indium tin oxide (ITO)/poly(3,4-ethlenedioxythiophene):poly(styrenesulphonic acid) (PEDOT: PSS)/CH<SUB>3</SUB>NH<SUB>3</SUB>I(PbI<SUB>2</SUB>)<SUB>1−X</SUB>(CuBr<SUB>2</SUB>)<SUB>X</SUB> (x=0, 0.025, 0.050, 0.075, and 0.100)/Phenyl-C61-butyric acid methyl ester (PCBM)/LiF/Al planar perovskite solar cells via solvent dripping process. Whereas the PbI<SUB>2</SUB>-DMSO<SUB>2</SUB> (DMSO:dimethyl sulfoxide) intermediate is not flowable during heat-treatment process due to the simultaneous melting and decomposition, the CuBr<SUB>2</SUB>-DMSO<SUB>2</SUB> intermediate is flowable so that the CH<SUB>3</SUB>NH<SUB>3</SUB>I(PbI<SUB>2</SUB>)<SUB>1−X</SUB>(CuBr<SUB>2</SUB>)<SUB>X</SUB> perovskite could form larger crystalline grains more reproducibly than the MAPbI<SUB>3</SUB> film. From the capacitance-voltage (C-V) characteristics and density functional theory (DFT) calculation, we could know that the conductivity of MAPbI<SUB>3</SUB> is much enhanced by CuBr<SUB>2</SUB> substitution of PbI<SUB>2</SUB> due to enhance charge carriers. Accordingly, the inverted CH<SUB>3</SUB>NH<SUB>3</SUB>I(PbI<SUB>2</SUB>)<SUB>1−X</SUB>(CuBr<SUB>2</SUB>)<SUB>X</SUB> (x=0.050) planar perovskite solar cells showed greatly improved device efficiency (average of 50 sample = 16.17 ± 0.79 %, best = 17.09 %) than the efficiency of MAPbI<SUB>3</SUB> device (average of 50 sample = 12.02 ± 0.86 %, best = 13.18 %) and did not show significant current density-voltage (J-V) hysteresis with respect to the scan direction.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Efficient metal halide substituted MAI(PbI<SUB>2</SUB>)<SUB>1−X</SUB>(CuBr<SUB>2</SUB>)<SUB>X</SUB> perovskite solar cells. </LI> <LI> Formation of more stable CuBr<SUB>2</SUB>-DMSO complex intermediate than PbI<SUB>2</SUB>-DMSO. </LI> <LI> CuBr<SUB>2</SUB> substitution of PbI<SUB>2</SUB> for highly reproducible large crystalline grains. </LI> <LI> Highly reproducible current density (J<SUB>SC</SUB>) and fill factor (FF). </LI> <LI> The possibility of Cu-doping and the much enhanced conductivity of perovskite. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>