Fabrication and comprehensive investigations on NBD-based luminescent solar concentrator

The design and development of innovative chromophoric materials for luminescent solar concentrators (LSCs) is an emerging area of research in the pursuit of low-cost photovoltaic technology. In this study, we devised and developed the optically active fluorescent dye NBDNH2 based on the skeleton of a benzoxadiazole. In NBDNH2, the electron donating amino group and the electron-withdrawing nitro group are the responsible for intramolecular charge transfer transition as well as fluorescence upon photoexcitation. The structural and photophysical properties of NBDNH2 dye have been meticulously investigated. In addition, the solvent-property relationships also investigated through time-resolved fluorescence and 1H NMR measurements. The photophysical studies reveal that the dye has a moderate Stokes shift, a long fluorescence lifetime and provides guidance for the development of LSCs. NBDNH2 was doped in polymethyl methacrylate (PMMA) to fabricate LSC devices. Due to promising optical properties, the NBDNH2 based LSC (5 x 5 x 0.3 cm3) showed the internal and external photon efficiencies as high as 29.4 % and 3.84 %, respectively. When connected with the photovoltaic cell, the champion device yielded power conversion efficiency of 1.32 % and 0.64 % with scattering and black background, respectively. Based on the findings, we unequivocally envisaged that the benzoxadiazole-based ICT probe is a prospective optical material for LSC applications.