Carbon Dot-Based Composite Films for Simultaneously Harvesting Raindrop Energy and Boosting Solar Energy Conversion Efficiency in Hybrid Cells
Lingyun Wang, Yu Wang, Han Wang, Guoqiang Xu, Aaron Döring, Walid A. Daoud, Jianbin Xu, Andrey L. Rogach, Yi Xi, Yunlong Zi
Abstract
Energy harvesting has drawn worldwide attention as a sustainable technology, while combining several approaches in a single device to maximize the overall energy output holds great promise to offer valuable technologies able to alleviate the energy crisis. Here, we present a hybrid cell composed of a silicon solar cell and a water-droplet-harvesting triboelectric nanogenerator (WH-TENG) with the capacity of harvesting both solar and raindrop energies. A transparent and solution processable carbon dot-based composite film is introduced as a dual-functional layer, acting as the transmittance enhancement layer of the solar cell as well as an ionic conductor of the WH-TENG. At an optimal loading of carbon dots in the composite, the significant enhancement of transmittance in visible spectral range increases the short-circuit current density of the solar cell, which results in an increase of its power conversion efficiency from 13.6% to 14.6%. In addition, the transparent WH-TENG consisting of fluorinated ethylene propylene as a triboelectrification layer can generate a maximum power of 13.9 μW by collecting raindrop energy. This study provides a promising strategy to boost the energy conversion through multiple sources with the aid of a dual-functional layer for enhancing solar cell performance as well as harvesting raindrop energy.