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Cu2ZnSnS4 (CZTS) compound is a promising candidate for thin‐film solar cells since its constituents are earth abundant and nontoxic. One of the major challenges to obtain a high‐quality CZTS absorber is to overcome the interfacial mismatch and formation of secondary phases between the CZTS and Mo substrate during the sulfurization process. Generally, the CZTS decomposed into Cu2S, ZnS, and SnS phases during sulfurization, and high‐density voids and cracks were observed. These micro‐ or macroreactions changed the stoichiometry of CZTS. In this paper, we present the insertion of a SnS buffer layer at Mo/CZTS interface to inhibit the undesired reaction and improve the thin‐film quality. The insertion of the thin SnS buffer layer prevented the CZTS absorber to contact directly with Mo and suppressed the present of secondary phases, pores and cracks. Crack‐free and smooth morphology was obtained. The cell efficiency was significantly improved.

This paper presents a novel method for enhancing the electroluminescence (EL) efficiency of ten-period silicon-rich oxide (SRO)/SiO2 superlattice-based light-emitting diodes (LEDs). A hydrogen ion beam (HIB) was used to irradiate each SRO layer of the superlattices to increase the interfacial roughness on the nanoscale and the density of the Si nanocrystals (Si NCs). Fowler-Nordheim (F-N) tunneling was the major mechanism for injecting the carriers into the Si NCs. The barrier height of the F-N tunneling was lowered by forming a nano-roughened interface and the nonradiative Pb centers were passivated through the HIB treatment. Additionally, the reflectance of the LEDs was lowered because of the nano-roughened interface. These factors considerably increased the slope efficiency of EL and the maximum output power of the LEDs. The lighting efficiency increased by an order of magnitude, and the turn-on voltage decreased considerably. This study established an efficient approach for obtaining bright Si NC/SiO2 superlattice-based LEDs.

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