Air-exposing microwave-assisted synthesis of CuInS₂/ZnS quantum dots for silicon solar cells with enhanced photovoltaic performance

Abstract

CIS/ZnS QDs were synthesized by microwave irradiation in air. The fabricated QDs/PMMA composite films were first applied to Si solar cells to improve the conversion efficiency by 3.8%.

Full‐visible spectrum emitting Zn–In–S:Cu/ZnS nanocrystals based on varying Cu concentrations and its application in white LEDs

“…As a result, the bandgap of NCs is enlarged. This blueshift phenomenon had been previously reported in those CuInS 2 /ZnS and AgInS 2 /ZnS core/shell NCs systems …”

“…With the reaction temperature increasing from 190°C to 200°C, the dopant PL intensity increases dramatically and reaches a maximum. Over this point, the intensity begins to dwindle because of the occurrence of Ostwald ripening . This abrupt enhancement in PL intensity should be ascribed to the transition of Cu doping mechanism from “dopant lattice adsorption” to “dopant lattice diffusion”, which was described in detail by Chen et al .…”

“…Figure A,B reveal the UV/vis absorption and emission spectra of undoped and Cu‐doped Zn–In–S NCs synthesized by a conventional hot injection method under the same reaction condition. Both Zn–In–S NCs and Zn–In–S:Cu d‐NCs show poorly resolved excitonic absorption feature, which is characteristic for ternary and quaternary alloyed semiconductor nanocrystals, coming from the irregular composition distribution among different NCs and/or intra‐bandgap states . However, the introduction of 10% Cu into Zn–In–S NCs markedly increased the absorption between 370 nm and 500 nm, which enables them to match well with the near UV‐blue InGaN LED chips.…”

“…Over this point, the intensity begins to dwindle because of the occurrence of Ostwald ripening. 32 This abrupt enhancement in PL intensity should be ascribed to the transition of Cu doping mechanism from "dopant lattice adsorption" to "dopant lattice diffusion", which was described in detail by Chen et al 38 The "dopant lattice diffusion" temperature for Zn-In-S:Cu system synthesized by a hot-injection process can be further derived to be about 195-205°C because the PL intensity starts to decrease when the reaction temperature is raised to 220°C.…”

“…Both Zn-In-S NCs and Zn-In-S: Cu d-NCs show poorly resolved excitonic absorption feature, which is characteristic for ternary and quaternary alloyed semiconductor nanocrystals, coming from the irregular composition distribution among different NCs and/or intra-bandgap states. [32][33][34][35][36][37] However, the introduction of 10% Cu into Zn-In-S NCs markedly increased the absorption between 370 nm and 500 nm, which enables them to match well with the near UV-blue InGaN LED chips. The corresponding emission spectrum is redshifted as large as 140 nm from 420 nm of the host Zn-In-S NCs to 560 nm of Zn-In-S:Cu d-NCs with the sharply enhanced emission intensity.…”