STRATEGY OF LIGHT HARVESTING IN PHOTOVOLATIC DEVICES WITH MICRO-NANO DISORDERED STRUCTURES

Abstract

Over the last few decades, photovoltaic devices have become an indispensable energy generator device, owing to infinite quantity of solar energy and nature friendly operation, replacing the limitation of natural resources [1]. Among them, multi-junction solar cells have attracted the attention of many studies working on highly efficient and durable solar devices due to their excellent longevity, stability, and energy conversion efficiency in the broadband solar spectrum. However, due to the high cost of multi-junction solar cell, generally solar module has small active area with unused region [2]. Here, by designing the affordable encapsulant layers, we report the geometry controllable disordered structure (GCDS) to capture the unused light that reaches blank areas and to reduce the surface reflection. As depicted in Fig. 1a, the encapsulant layer shows a disordered structure which is fabricated by self – organized thermal dewetting method and the encapsulant layer was replicated with PDMS (Fig. 1b). To evaluate the optical reaction of structures, we changed the average periods from 300 nm to 1200 nm (Fig. 1c). Resultingly, in case of subwavelength period, (i.e., period is 300 nm) specular transmittance shows an anti-reflection property, on the other hand, periods of 900 nm and 1200 nm show a diffractive regime (Fig. 1d). As represented in Fig. 1e, the diffusive properties are experimentally confirmed using green laser beam (λ=532 nm).