Recent Advances in Perovskite Solar Cells: Morphology Control and Interfacial Engineering

147

117

Figure 20. a) Modeled J − V characteristics of a perovskite device comprising ions but no traps. b) Modeled I -V characteristics of perovskite devices comprising ions and no traps for varying ion densities. c) Modeled J − V characteristics of perovskite device comprising ions and traps with varying ion mobility as indicated in the legend at a sweep rate of 100 kV s −1 . d) Modeled J -V characteristics of a perovskite device comprising ions and bulk traps. [ 211 ] 2015, American Chemical Society. e) Flow directions of the charged ion species in a Pb|MAPbI 3 |AgI |Ag cell under electrical bias. f) Images for surfaces A and B and g) a scanning electron microscope (SEM) image of surface B on the Pb pellet. h) The same cell confi guration to Figure 23 e. i) Images of each pellets after aging at 50 °C for a week in Ar atmosphere (no current stressing). Reproduced with permission. [ 212 ]

Section: Design Fundamentalsmentioning

confidence: 99%

The Progress of Interface Design in Perovskite‐Based Solar Cells

Fan

Huang

Wang

et al. 2016

147

117

“…Hybrid organometal trihalide perovskite (CH 3 NH 3 PbX 3 , X = Cl, Br, I) solar cells have been rapidly developed over the past few years because of their intriguing optoelectronic properties, such as high absorption coefficient for efficient light harvesting, long charge carrier lifetimes and diffusion lengths, relatively insensitivity to electronic trap states, and facile tuning of bandgaps by varying compositions . Due to the excellent charge transport properties of perovskite semiconductors, they can be adopted in various types of device structures including the one based on mesoporous metal oxide scaffold or p–i–n type planar‐heterojunction (PHJ) perovskite solar cells (PVKSCs) . The later one has recently attracted increasing attentions due to its relatively simple device architecture and its potential for being fabricated using low‐temperature, large‐area coating processes …”

Section: Introductionmentioning

confidence: 99%

Amino‐Functionalized Conjugated Polymer as an Efficient Electron Transport Layer for High‐Performance Planar‐Heterojunction Perovskite Solar Cells

Sun

Yip

et al. 2015

Self Cite

311

188

An amino‐functionalized copolymer with a conjugated backbone composed of fluorene, naphthalene diimide, and thiophene spacers (PFN‐2TNDI) is introduced as an alternative electron transport layer (ETL) to replace the commonly used [6,6]‐Phenyl‐C61‐butyric acid methyl ester (PCBM) in the p–i–n planar‐heterojunction organometal trihalide perovskite solar cells. A combination of characterizations including photoluminescence (PL), time‐resolved PL decay, Kelvin probe measurement, and impedance spectroscopy is used to study the interfacial effects induced by the new ETL. It is found that the amines on the polymer side chains not only can passivate the surface traps of perovskite to improve the electron extraction properties, they also can reduce the work function of the metal cathode by forming desired interfacial dipoles. With these dual functionalities, the resulted solar cells outperform those based on PCBM with power conversion efficiency (PCE) increased from 12.9% to 16.7% based on PFN‐2TNDI. In addition to the performance enhancement, it is also found that a wide range of thicknesses of the new ETL can be applied to produce high PCE devices owing to the good electron transport property of the polymer, which offers a better processing window for potential fabrication of perovskite solar cells using large‐area coating method.

“…The most commonly used inverted device architecture for PHJ PVSCs is ITO/poly(3,4‐ethylenedioxythiophene):poly (styrenesulfonate) (PEDOT:PSS)/perovskite/phenyl‐C61‐butyric acid methyl ester (PC 61 BM)/metal, in which the PEDOT:PSS and PC 61 BM serve as hole‐transporting layer (HTL) and electron‐transporting layer (ETL), respectively. Recent advances in optimizing the perovskite morphology and cathode interface have resulted in high PCE in the PEDOT:PSS‐based PVSCs . However, the open‐circuit voltage ( V oc ) (0.90–0.95 V) in the PEDOT:PSS‐based PVSCs is typically lower than that (≈1.05 V) obtained from meso‐superstructured PVSCs due to the mismatched workfunction between PEDOT:PSS and the valence band of perovskite semiconductor.…”

Section: Introductionmentioning

confidence: 99%

Improving Film Formation and Photovoltage of Highly Efficient Inverted‐Type Perovskite Solar Cells through the Incorporation of New Polymeric Hole Selective Layers

Xue

Chen

Liu

et al. 2015

Self Cite

160

117

effi ciency (PCE) of the record perovskite solar cells (PVSCs) has already reached over 20%, [ 6 ] making it a potential contender for new generation photovoltaic technology.The perovskite semiconductors can be adopted in various types of solar cell architectures including perovskite-sensitized solar cells, [ 1 ] meso-superstructured solar cells and planar heterojunction (PHJ) solar cells. [ 7,8 ] The latter one, which has a device architecture resembles that of polymer solar cells, is particularly attractive for potential commercialization due to the simplicity of the device structure, low-temperature solution processibility, as well as the potential of large-scale manufacturing using a continuous coating technique on fl exible substrates. [8][9][10][11][12][13][14] The most commonly used inverted device architecture for PHJ PVSCs is ITO/ poly(3,4-ethylenedioxythiophene):poly (styrenesulfonate) (PEDOT:PSS)/perovskite/ phenyl-C61-butyric acid methyl ester (PC 61 BM)/metal, in which the PEDOT:PSS and PC 61 BM serve as hole-transporting layer (HTL) and electron-transporting layer (ETL), respectively. Recent advances in optimizing the perovskite morphology and cathode interface have resulted in high PCE in the PEDOT:PSSbased PVSCs. [15][16][17][18][19][20][21][22][23] However, the open-circuit voltage ( V oc ) (0.90-0.95 V) in the PEDOT:PSS-based PVSCs is typically lower than that (≈1.05 V) obtained from meso-superstructured PVSCs due to the mismatched workfunction between PEDOT:PSS and the valence band of perovskite semiconductor. Therefore, new anode modifi cation is also important to fully unveil the potential of inverted PHJ PVSCs. [ 3,7,[24][25][26][27] Although several inorganicbased HTLs have been exploited to enhance the V oc and PCE of PHJ PVSCs, the severe surface charge recombination due to the presence of surface traps in the metal oxide limits their performance and the high temperature sintering process (>300 °C) required for preparing oxide fi lms with high crystallinity make it incompatible for roll-to-roll printing process and limits its practical applications. [ 12,[28][29][30][31] PEDOT:PSS is generally used as anode interlayer because of its solution processibility, good electrical property, low processing temperature, and commercial availability. Nevertheless,