In this paper, oleylammonium polysulfides molecules were self-assembled on an etched perovskite film, leading to an enhancement in moisture stability of the devices.

Organometallic halide perovskite solar cells (PSCs) are rapidly evolving as the promising photovoltaic technologies with high record efficiency over 24%. The inorganic p‐type semiconductor NiOx is extensively used as important hole transport layers for the realization of stable and hysteresis‐free solar cells due to their good electronic properties, facile fabrication, and excellent chemical endurance. However, the critical issues of NiOx films including poor intrinsic conductivity and mismatched band alignment limit further improvement of the device performance. Herein, it is demonstrated that a versatile alkaline earth metal (Mg, Ca, Sr, and Ba) doping strategy can effectively engineer the electronic properties of NiOx contacts in inverted planar PSCs. Alkaline earth metal doping can deepen valence band maximum and enhance the hole conductivity of NiOx films, which better aligns the energy band in solar cells. The champion device based on Sr‐doped NiOx films attains a power conversion efficiency of 19.49% with a high open‐circuit voltage (VOC) of 1.14 V for NiOx‐based CH3NH3PbI3 devices. The resulted device shows negligible hysteresis and high stability as well. This finding provides a systematic doping strategy to further improve the performance of inverted planar PSCs.

Cesium lead halide perovskites are promising alternatives as light-absorbing materials for perovskite solar cells with excellent thermal stability, but their inferior power conversion efficiency (PCE) and ambient instability are impeding...

Perovskite solar cells (PSCs) are expected to profoundly impact the photovoltaic society on account of its high-efficiency and cost-saving manufacture. As a key component in efficient PSCs, the hole transport layer (HTL) can selectively collect photogenerated carriers from perovskite absorbers and prevent the charge recombination at interfaces. However, the mainstream organic HTLs generally require multi-step synthesis and hygroscopic dopants that significantly limit the practical application of PSCs. Here, a self-organized percolative architecture composed of narrow bandgap oxides (e.g., Co 3 O 4 , NiO, CuO, Fe 2 O 3 , and MnO 2 ) and wide bandgap SrCO 3 oxysalt as efficient HTLs for PSCs is presented. The percolation of dual phases offers nanosized hole transport pathways and optimized interfacial band alignments, enabling significantly improved charge collection compared with the single phase HTLs. As a consequence, the power conversion efficiency boosted from 8.08% of SrCO 3 based device and 15.47% of Co 3 O 4 based device to 21.84% of Co 3 O 4 -SrCO 3 based one without notable hysteresis. The work offers a new direction by employing percolative materials for efficient charge transport and collection in PSCs, and would be applicable to a wide range of opto-electronic thin film devices.

An inorganic NiCoOx hole conductor was developed as an HTM for PSCs. The champion device yielded a PCE of 20.03%.