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Here, a pseudo-solution-phase ligand exchange (p-SPLE) strategy is developed for fabricating a CsPbI3 quantum dot (QD) solar cell. Using short organic aromatic ligands to partly replace the long-chain ligands in a QD solution, the p-SPLE treated CsPbI3 QD solar cell had an enhanced power conversion efficiency of up to 14.65% together with improved stability.

Facile hydrothermally synthesized PbSnS2 nanosheets with various morphologies were developed to obtain high performance electrode materials for supercapacitors. A precipitation–dissolution mechanism was proposed to demonstrate the growth process of PbSnS2. The as-prepared nanosheets exhibited superior capacitance (678.8 F g−1 at 50 mV s−1) and a long cycle life (95.5% capacitance retention after 100 000 cycles at 5 A g−1).

This work describes a facile one-step method to synthesize PbS hierarchical architectures with excellent supercapacitive performance. The as-prepared PbS sample shows a self-similar fern-like morphology. A unit has four or eight micro-trunks with the size of 10 ± 1 μm, which consist of ordered secondary nano-leaves with the thickness of 200 ± 20 nm and the spacing of about 100 nm. The fractal fern-like PbS sample owns a high specific capacitance of 498 F/g at a discharge current density of 2 A/g, while the value still retains 74% (369 F/g) at a big discharge current density of 20 A/g. The equivalent series resistance of the as-prepared sample is only 1.05 Ω. Moreover, the fractal fern-like PbS sample exhibits a surprising long-term durability which can keep 95.9% capacitance retention over 60,000 charge/discharge cycles at a charge/discharge current density of 5 A/g. The as-prepared PbS sample shows a stable energy density of 11.5 Wh/kg at the power density of 200 W/kg, and still remains 8.2 Wh/kg at 4000 W/kg.

A facile Co foam@Co3O4 porous nanosheet arrays (CPNA) has been synthesized via an in-situ oxidization reaction and there are tiny pores with diameter of 5 ± 2 nm that evenly distribute on the nanosheet with thickness of 3 ± 1 nm. The as-prepared Co foam@CPNA sample owns an ultrahigh specific capacitance of 2585 F g-1 at 5 mV s−1 and the resistance is only 1.09 Ω. It also shows a remarkable long-term stability of 77.5% capacitance retention over 20,000 charge/discharge cycles at 5 A g−1. The results suggest that the in-situ growth of Co3O4 porous nanosheet arrays on the Co foam plays an important role in its excellent electrochemical performance.

The solution-processed solar cells based on colloidal quantum dots (QDs) reported so far generally suffer from poor thickness tolerance and it is difficult for them to be compatible with large-scale solution printing technology. However, the recently emerged perovskite QDs, with unique high defect tolerance, are particularly well-suited for efficient photovoltaics. Herein, efficient CsPbI3 perovskite QD solar cells are demonstrated first with over 1 µm-thick active layer by developing an internal P/N homojunction. Specifically, an organic dopant 2,2'-(perfluoronaphthalene-2,6-diylidene) dimalononitrile (F6TCNNQ) is introduced into CsPbI3 QD arrays to prepare different carrier-type QD arrays. The detailed characterizations reveal successful charge-transfer doping of QDs and carrier-type transformation from n-type to p-type. Subsequently, the P/N homojunction perovskite QD solar cell is assembled using different carrier-type QDs, delivering an enhanced power conversion efficiency of 15.29%. Most importantly, this P/N homojunction strategy realizes remarkable thickness tolerance of QD solar cells, showing a record high efficiency of 12.28% for a 1.2 µm-thick QD active-layer and demonstrating great potential for the future printing manufacturing of QDs solar cells.