مقاله انگلیسی رایگان در مورد فتوولتائیک پلیمرهای شفاف برای برداشت انرژی خورشیدی – الزویر 2018

Harvesting energy from the sun is attracting increasing attention due to the challenges arising from our continued dependence on fossil fuels. In the past two decades, polymer photovoltaics (PV) based on bulk-heterojunction (BHJ) structure have become a promising alternative energy option due to their lightweight properties, environmental friendliness, and solution processability.1–5 The capability for solution processing especially provides the possibility of fabricating organic devices on flexible substrates and over large device areas with relatively simple equipment and low costs. The certified power conversion efficiency (PCE) of organic PV (OPV) has already exceeded 12% by a combination of novel materials and morphology optimization.6,7 Due to the nature of molecular orbitals, the absorption spectra of organic semiconductors are not continuous as in inorganic semiconductors. This results in a major shortcoming for single-junction polymer PV devices in terms of their insufficient light absorption. However, this ‘‘disadvantage’’ of polymer PV can actually open a door to a new opportunity: visible region transparency. The active layer in a transparent organic photovoltaics (TOPV) device is required to exhibit high transparency in the visible region. In this article, to simplify the conditions in different optical transparencies, we use ‘‘TOPV’’ to represent transparent, semi-transparent, and translucent OPV. According to the energy distribution of the AM 1.5G solar spectrum, 51% of the solar energy is distributed within the infrared (IR) region (shown in Figure 1A).8 As a result, the theoretical PCE of polymer PV with only IR absorption is able to be as high as the device with only visible absorption, or even better. Although intensive attention has been paid to OPV since the 1990s, the potential of TOPV was not realized until 2006.10,11 The typical TOPV device is shown in Figure 1B. In the last decade, the progress in TOPV development was relatively slow due to the low PCE. Recently, because of the rapid developments of novel and visibly transparent semiconductors and electrodes, important studies on different aspects of TOPV have been carried out. Herein, we present a review perspective on the developments of TOPV devices and their potential applications, with a goal of inspiring new ideas that could achieve superior transparency and PCE.