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All-inorganic perovskite solar cells (IPSCs) have gained massive attention due to their less instability against common degradation factors (light, heat, and moisture) than their organic–inorganic hybrid counterparts. Inorganic perovskites bear a general formula of CsPbX3(X = Cl, I, Br). The mixed halide CsPbIBr2perovskite possesses an intermediate band gap of 2.03 eV with enhanced stability, which is still available for photovoltaic applications and the research focus of this work. We present a synergistic approach of pre-heated solution dropping with inorganic additive inclusion to deposit the organic-free triple anion CsPbIBr2PSC. Erbium (Er)-passivated triple-anion CsI(PbBr2)0.97(ErCl3)0.03IPSCs with inorganic carrier selective layers (CTLs), that is, organic-free, are fabricated with enhanced carrier diffusion length and crystalline grain size while lessening the grain boundaries near perovskite active layer (PAL)-bulk/carrier selective interfaces. As a result, the trap-state densities within the perovskite bulk were suppressed with stabilized CTL/PAL interfaces for smooth and enhanced carrier transportation. Therefore, for the first time, we contradict the common belief of VOCloss due to halide segregation, as a nice VOCof about 1.34 V is achieved for an organic-free IPSC through enriching initial radiative efficiency, even when halide segregation is present. The optimized organic-free IPSC yielded a power conversion efficiency of 11.61% and a stabilized power output of 10.72%, which provides the potential opportunity to integrate into agrivoltaics (AgV) projects.

The decoration of n-type silicon (n-Si) with bimetallic NiFe nanoparticles has been shown to be an effective approach in achieving efficient photoelectrochemical (PEC) water oxidation. However, the ratio of Ni/Fe was not precisely controlled in the previous studies and the respective effects of Ni and Fe on the PEC performance have not been systematically investigated. In this work, dual-source electron beam evaporation is employed to deposit NiFe nanoparticles on n-Si with precisely controlled Ni/Fe ratios. The NiFe/SiOx/n-Si photoanode records an applied bias photon-to-current efficiency (ABPE) of 3.03 ± 0.10% with a Ni/Fe ratio of 3:1. However, the stability of the photoanode decreases with higher Fe content, which is ascribed to the leaching of Fe catalytic sites. With the addition of Fe ions into the electrolyte, the ABPE is maintained at 3.12 ± 0.04% and the stability is significantly improved. Our results highlight a potential method to achieve efficient and stable PEC water oxidation with this simple device architecture.

Perovskite single crystals have gained enormous attention in recent years due to their facile synthesis and excellent optoelectronic properties including the long carrier diffusion length, high carrier mobility, low trap density, and tunable absorption edge ranging from ultra-violet (UV) to near-infrared (NIR), which offer potential for applications in solar cells, photodetectors (PDs), lasers, etc. In this review, we summarized the synthesis, properties, and applications of organic-inorganic mixed and all-inorganic perovskite single crystals, particularly through the solution synthesis approach. Challenges towards the crystal growth and stability with future perspectives were also briefly described at the end of this manuscript.