Modified Fullerenes for Efficient Electron Transport Layer‐Free Perovskite/Fullerene Blend‐Based Solar Cells

Abstract

A variety of novel chemically modified fullerenes, showing different electron-accepting capabilities, has been synthesized and used to prepare electron transport layer (ETL)-free solar cells based on perovskite/fullerene blends. In particular, isoxazolino[60] fullerenes are proven to be a good candidate for processing blend films with CH NH PbI and obtaining enhanced power conversion efficiency (PCE) ETL-free perovskite solar cells (PSCs), improving the state-of-the-art PCE (i.e., 14.3 %) for this simplified device architecture. A beneficial effect for pyrazolino and methano[60]fullerene derivatives versus pristine [60]/fullerene is also shown. Furthermore, a clear correlation between the LUMO energy level of the fullerene component and the open circuit voltage of the solar cells is found. Apart from the new knowledge on innovative fullerene derivatives for PSCs, the universality and versatility of perovskite/fullerene blend films to obtain efficient ETL-free PSCs is demonstrated.

Hindered Amine Light Stabilizers Increase the Stability of Methylammonium Lead Iodide Perovskite Against Light and Oxygen

“…Methylammonium lead iodide perovskite (MAPI) solar cells constitute an emerging photovoltaic technology that in recent years has shown an outstanding improvement in power conversion efficiency, surpassing 21 % . However, despite this significant progress, poor stability of perovskite devices remains a major issue.…”

Cove‐Edge Nanoribbon Materials for Efficient Inverted Halide Perovskite Solar Cells

“…These layers are invaluable because they determine the polarity of the device,i mprove stability,p assivate surface charge traps,a nd aid in chargeextraction transport from the active layer to the electrodes ( Figure 1). [11] However,the ETM is limited mainly to fullerenes such as PC 61 BM and other derivatives, [12][13][14][15][16][17] and there are few examples of efficient non-fullerene inverted PSCs reported. Despite the lower PCE at present, the inverted planar devices, which are based on p-i-n configurations,a re attractive because the relatively simple device architecture is promising for flexible devices and is amenable to low-temperature and scalable fabrication techniques.…”

Simple, Robust, and Going More Efficient: Recent Advance on Electron Transport Layer‐Free Perovskite Solar Cells

“…Pascual et al deposited an MAPbI 3 :C 70 blend layer to fabricate ETL-free devices. [97] A highest PCE of 14.3% was demonstrated. As a result, the MAPbI 3 :C 70 based PSCs exhibited larger recombination resistance than the pristine MAPbI 3 based ones, showing a highest PCE of 13.6%.…”

“…Xiao and co-workers reported robust inverted ETL-free PSCs, the device with Ti interlayer maintained nearly 90% and 77% of the initial PCE after 15 and 40 days, respectively, [109] which represents a significant device stability improvement with metal cathode directly in contact with perovskite layer. [97] In the work by Han et al, the photostability of the champion ETL-free devices without encapsulation was measured under continuous light soaking (1 sun) under ambient conditions (25% humidity, 25 °C), after 192 h of irradiation, the device remains >90% of its initial PCE, which is encouraging result for robust ETL-free PSC. [111] As for the photostability, Pascual and co-workers demonstrated that introducing C 70 into perovskite film significantly improves the photostability of ETL-free PSCs as the device suffered only about 10% PCE reduction after 3 h storage under continuous illumination.…”