Self-embedded silicon nanoparticle-based films for transparent luminescent solar concentrators

Silicon nanoparticles (SiNPs) were synthetized and employed in self-embedded films as luminophore to fabricate transparent luminescent solar concentrators (SiNPLSCs). The nanoparticles were obtained from the reduction of (3-aminopropyl) triethoxysilane (APTES) by sodium ascorbate. Besides the reduction of APTES into SiNPs, a silicate matrix host is obtained and further employed as the nanoparticles support for the photoluminescent film. The SiNPs exhibit absorption below 450 nm extending to the ultraviolet region; while emitting in broad bands from 400 to 650 nm, whose maximum depends on the excitation wavelength. The as-synthesized solution containing both the SiNPs and the matrix host was deployed directly on glass substrates to create the SiNPLSCs. The devices present high transparencies with transmittances above 85% over the visible region, producing average visible transmission (AVT) values of 88.78% and great color rendering index (CRI) of 98.26. The photoluminescent properties of the SiNPLSCs were measured at the edges of the devices under different excitation wavelengths and solar simulated light. The LSCs were physically attached to commercial silicon solar cells (PV) to study the photovoltaic performance of the LSC-PV systems. According to I-V measurements under solar simulated light, the SiNPLSC-PV system showed power conversion efficiency of 0.97% and optical efficiency of 1.04%. These results are significant since the device presents high transparency with a feasible and attractive fabrication method, properties that are desired for their incorporation as building integrated photovoltaics and photovoltaic windows.