Rondiya, Sachin R., Jadhav, Yogesh A., Živković, Aleksandar, Jathar, Sagar B., Rahane, Ganesh K., Cross, Russell W., Rokade, Avinash V., Devan, Rupesh S., Kolekar, Sadhu, Hoye, Robert L.Z., Ghosh, Hirendra N., de Leeuw, Nora H., Jadkar, Sandesh R., and Dzade, Nelson Y.
• Synthesis of Cu 2 CdSnS 4 (CCTS) and Cu 2 ZnSnS 4 (CZTS) nanocrystals using low-cost homemade hot-injection method. • First-principles DFT calculated phonon dispersion shows that both CCTS and CZTS are stable at ambient pressure. • Bandgap reduction from 1.51 eV (kesterite- CZTS) to 1.1 eV (stannite-CCTS) is demonstrated. • Fabricated CCTS nanocrystals sensitize solar cell exhibits a power conversion efficiency of 1.1% compared to 0.25% for CZTS. [Display omitted] The Earth-abundant kesterite Cu 2 ZnSnS 4 (CZTS) exhibits outstanding structural, optical, and electronic properties for a wide range of optoelectronic applications. However, the efficiency of CZTS thin-film solar cells is limited due to a range of factors, including electronic disorder, secondary phases, and the presence of anti-site defects, which is a key factor limiting the V oc. The complete substitution of Zn lattice sites in CZTS nanocrystals (NCs) with Cd atoms offers a promising approach to overcome several of these intrinsic limitations. Herein, we investigate the effects of substituting Cd2+ into Zn2+ lattice sites in CZTS NCs through a facile solution-based method. The structural, morphological, optoelectronic, and power conversion efficiencies (PCEs) of the NCs synthesized have been systematically characterized using various experimental techniques, and the results are corroborated by first-principles density functional theory (DFT) calculations. The successful substitution of Zn by Cd is demonstrated to induce a structural transformation from the kesterite phase to the stannite phase, which results in the bandgap reduction from 1.51 eV (kesterite) to 1.1 eV (stannite), which is closer to the optimum bandgap value for outdoor photovoltaic applications. Furthermore, the PCE of the novel Cd-substituted liquid junction solar cell underwent a four-fold increase, reaching 1.1%. These results highlight the importance of substitutional doping strategies in optimizing existing CZTS-based materials to achieve improved device characteristics. [ABSTRACT FROM AUTHOR]