Doped Charge‐Transporting Layers in Planar Perovskite Solar Cells

Abstract

mesostructured semiconductor (m-TiO 2 , m-SnO 2 , and m-ZnO) or insulating (Al 2 O 3 , and ZrO 2 ) metal oxide as the electrontransporting layer (ETL) and/or scaffold layer is fabricated on the compact layer, following by a coating of the perovskite active layer. A hole-transporting layer (HTL) is then deposited, followed by the evaporation of a metal anode. [7][8][9] However, the deposition of the mesoscopic ETLs generally needs a processing temperature which is higher than 450 °C to improve the optoelectrical properties of the mesoporous layer. [10] The mesostructured semiconductor scaffold can be totally removed when fabricating the planar devices with an n-i-p structure (e.g., fluorine-doped tin oxide (FTO)/TiO 2 /MAPbI 3−x Cl x /Spiro-OMeTAD/Ag). In addition, planar PSCs with an p-i-n construction have also been fabricated by using poly(3,4-ethylene dioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) as the hole-transporting layer and fullerene derivatives as the electron-transporting layer. [11] Compared to mesoscopic devices, the fabrication of planar heterojunction (PHJ) PSCs does not need high temperature process, offering possibilities of achieving flexible devices on plastic substrates and demonstrating potential application in lightweight and wearable electronics. Great efforts have been devoted to fabricate high-performance planar PSCs including the perovskite morphology and crystal optimization, [12,13] the optimal selection of HTLs, and the rational design of ETLs. [14,15] Particularly, both HTL and ETL play very important role in enhancing the device performance of the planar PSCs. For example, 6,6-phenylC61butyric acid methyl ester (PCBM) is a commonly used ETM in p-i-n PSCs. After that, more and more electrontransporting materials (ETMs), such as TiO 2 , [16] ZnO, [17] WO 3 , [18] SnO 2 , [19] and ZnSnO 4 [20] with decreased cost, are developed for n-i-p PSCs. For HTMs, 2,2′,7,7′-tetrakis-(N,N-dip-methoxyphenylamine) 9,9′-spirobifluorene (Spiro-OMeTAD), poly-3-hexylthiophene (P3HT), and poly-triarylamine (PTAA) are utilized in n-i-p PSCs. [21] What is more, PEDOT:PSS, NiO, CuI, CuSCN, CuO x , MoO x , graphene oxide (GO), and reduced graphene oxide (rGO) have been widely employed as HTMs in p-i-n PSCs. [22][23][24][25][26][27] With significant efforts on proposing device architectures, optimizing perovskite compositions, developing new deposition techniques for high-quality perovskite films, and designning various HTLs and ETLs, the PCE of the planar PSCs has been reached over 23%. Nevertheless, PSCs are still in the early stages for commercialization owing to their existing issues such as unsatisfied efficiency, unstable device performance, Organometal halide perovskite solar cells (PSCs) are brought to the forefront of research focus in photovoltaics field with a rapid efficiency rising over 22% in the past few years. Interface engineering with suitable hole-transporting layer (HTL) and/or electron-transporting layer (ETL) plays very important roles in controlling the charge carrier behavior in...

N‐type Doping of Organic‐Inorganic Hybrid Perovskites Toward High‐Performance Photovoltaic Devices

“…Doping is an effective strategy which has been widely used in inorganic and organic semiconductor based photovoltaic devices. A suitable doping can adjust optical and electrical properties of semiconductor materials with a large degree of freedom . Particularly, the incorporation of dopants offers a route to improve the optoelectronic property of inorganic and organic hybrid perovskites by endowing them with new features.…”

“…A suitable doping can adjust optical and electrical properties of semiconductor materials with a large degree of freedom. [34][35][36][37][38][39] Particularly, the incorporation of dopants offers a route to improve the optoelectronic property of inorganic and organic hybrid perovskites by endowing them with new features.…”

γ‐Ga2O3 Nanocrystals Electron‐Transporting Layer for High‐Performance Perovskite Solar Cells

“…Currently, perovskite solar cells (PSCs) have attained a record PCE of 24.2% . To further improve the performance of PSCs, strategies such as doping and interfacial engineering have been implemented. Other approaches involve the development of new perovskite materials, device structures, fabrication methods and device components (hole transporting layers [HTLs], electron transporting layers [ETLs], buffer layers, etc.).…”

Enhanced Electrical Property of Compact TiO2 Layer via Platinum Doping for High‐Performance Perovskite Solar Cells

“…The ETL interfacial layer between the perovskite absorbers and the electrode is strongly required to collect photo‐generated charge carriers generated in perovskite absorbers and prevent the recombination of charge carriers at the interfaces, thus ensuring a higher power conversion efficiency (PCE) . The materials selected as the ETL can be classified into three categories: metal oxides, organic small molecules, and composites . Among them, titanium dioxide (TiO 2 ) has been considered as the promising material for energy storage, photo‐catalysis, and photovoltaic technologies .…”