Tailoring organic bulk-heterojunction for charge extraction and spectral absorption in CsPbBr3 perovskite solar cells

Abstract

All-inorganic CsPbBr 3 perovskite solar cells (PSCs) are promising candidates to balance the stability and efficiency issues of organic-inorganic hybrid devices. However, the large energy barrier for charge transfer and narrow spectral response are still two challenging problems for performance improvement. We present here an organic bulkheterojunction {poly(3-hexylthiophene-2,5-diyl):[6,6]-phenyl C61 butyric acid methyl ester (P3HT : PCBM)} photoactive layer to boost the charge extraction and to widen the spectral absorption, achieving an enhanced power conversion efficiency up to 8.94% by optimizing the thickness of P3HT: PCBM photoactive layer, which is much higher than 6.28% for the pristine CsPbBr 3 device. The interaction between the carbonyl group in PCBM and unsaturated Pb atom in the perovskite surface can effectively passivate the defects and reduce charge recombination. Furthermore, the coupling effect between PCBM and P3HT widens the spectral response from 540 to 650 nm for an increased short-circuit current density. More importantly, the devices are relatively stable over 75 days upon persistent attack by 70% relative humidity in air condition. These advantages of high efficiency, excellent long-term stability, cost-effectiveness and scalability may promote the commercialization of inorganic PSCs.

Efficient thin-film perovskite solar cells from a two-step sintering of nanocrystals

“…12,26,41 Recent studies indicate that the PCE of CsPbBr 3 solar cells can be greatly improved to be >10% when gold electrode is replaced by carbon electrode. [42][43][44][45] It is expected that significant improvement could be further achieved through optimizing the device configuration by taking advantages of the carbon electrode for CsPbBr 3 solar cells.…”

High‐Efficiency Carbon‐Based CsPbIBr2 Solar Cells with Interfacial Energy Loss Suppressed by a Thin Bulk‐Heterojunction Layer

“…Light with wavelengths longer than 600 nm will be absorbed by the BHJ layer and the separation of electron-hole pairs will occur at the interfaces of P3HT and PC 61 BM. At the same time, because the perovskite materials have bipolar transport properties with high electron and hole mobility, [15,31] the electrons generated in the BHJ layer can be transported along the electron acceptor material (PC 61 BM) network to the CsPbIBr 2 film and then transfer through the CsPbIBr 2 film to the TiO 2 ETL; meanwhile the holes are collected by the carbon electrode.…”

Direct Molecule Substitution Enabled Rapid Transformation of Wet PbBr2(DMF) Precursor Films to CsPbBr3 Perovskite

“…Compared with organic metal halide perovskites, all-inorganic halide perovskites, CsPbX 3 (X = I, Br, and Cl), have enhanced compositional, thermal, and optical stability, especially CsPbBr 3 , which, meanwhile, shows excellent stability against humidity. − Direct band gap CsPbBr 3 , with a corner-shared [PbBr 6 ] 4– octahedron in a 3D framework, has large absorption cross-sections and superior optoelectrical properties . Recently, it has been widely applied in solar cells, − light-emitting diodes, − photodetectors, − lasers, , and so on. , …”