Abstract
Due to well-developed manufacturing process for monocrystalline silicon solar cell, monocrystalline silicon solar cell leads in the solar cell manufacturing market. However, because of the restriction of energy bandgap of Si (i.e., 1.12 eV), the monocrystalline silicon solar cell has much lower photo-sensitivity to ultraviolet light (λ<400 nm) and infrared light (λ>1200 nm) than visible light. Nowadays, lots of researches develop to utilize the method called light harvesting to enhance the efficiency of monocrystalline silicon solar cell by converting ultraviolet light or infrared light to the light which is more photo-sensitive to monocrystalline silicon solar cell.In this study, we report on the use of a novel fluorescent polymer doped in the EVA (ethylene vinyl acetate copolymer) encapsulation layer of solar module for light harvesting. The utilization of fluorescent polymer not only can improve the miscibility in EVA matrix but suppress the quenching effect which would lower the fluorescent intensity. And this fluorescent polymer can absorb ultraviolet light, then emit fluorescent light which is more photo-sensitive to monocrystalline silicon solar cell proved by fluorescence spectrophotometer. The synthesis of fluorescent polymer, 9-APCL, was carried out through ring-opening polymerization (ROP) by taking the organic fluorescent molecules with mono-hydroxyl group: 9-(hydroxymethyl) anthracene as ROP initiator and ε-caprolactone as monomers. Moreover, the chemical structure and the thermal properties of 9-APCL were characterized by FTIR, NMR, GPC, TGA and DSC.The blending of 9-APCL and EVA was prepared in a rotating one-screw extruder. And then the film with thickness approximate 0.5 mm was prepared via thermally pressing the blended pellet by a Laminator. In order to study the miscibility of 9-ACPL and EVA, the morphology was examined by scanning electron microscopy. Subsequently, we used both neat EVA and modified EVA respectively as encapsulant to make monocrystalline silicon solar modules. Finally the characterization of photovoltaic including External Quantum Efficiency (EQE) and I-V curve were measured. The best-performed solar module in this study shows an enhancement of approximate 50% in EQE for the wavelength from 300 to 400 nm, which results in 0.8% higher overall efficiency relatively to the solar module which encapsulated with neat EVA.This study has shown that an enhancement in the performance of monocrystalline silicon solar modules can be achieved, without any modification to the well-established manufacturing process.?