Selenium‐Based Solar Cell with Conjugated Polymers as Both Electron and Hole Transport Layers to Realize High Water Tolerance as well as Good Long‐Term and Thermal Stability

Abstract

Solar cells with varied absorbers, ranging from crystalline silicon to perovskite materials, are very vulnerable to water. Expensive and complicated encapsulation is needed to protect the devices. Thus, it is highly desirable to achieve encapsulation‐free solar cells with high water tolerance. Herein, encapsulation‐free selenium (Se)‐based solar cells (SSCs) with hydrophobic polymers as electron and hole transport layers are presented and can successfully tolerate the aqueous conditions. Moreover, it is found that the photocurrent–time curve under the aqueous/ambient environment can be smoothly fitted into the first‐order exponential models. The photocurrent of water‐soaking SSCs can recover to its original value after drying in the air, which proves the great water tolerance of fabricated SSCs. Furthermore, the SSCs also show good long‐term and thermal stability. The viability of encapsulation‐free SSCs under a harsh environment provides opportunities to further explore the interactions among light, water, and solar cells as well as make large‐scale industrialization applications of SSCs much easier.

Semitransparent Selenium Solar Cells as a Top Cell for Tandem Photovoltaics

“…[17,18] Further studies have demonstrated encapsulationfree tolerance toward aqueous conditions by use of hydrophobic polymer transport layers. [19] In this study, we report the first bifacial selenium solar cell with a state-of-the-art performance above 5% PCE from frontside illumination (through the n-type contact) and 2.7% PCE from back-side illumination (through the p-type contact) for devices with contact areas above 0.4 cm 2 . For these contact area sizes, we show better bifacial cell performance than any reported monofacial cells of similar size.…”

“…[ 17,18 ] Further studies have demonstrated encapsulation‐free tolerance toward aqueous conditions by use of hydrophobic polymer transport layers. [ 19 ]…”

Sustainable Recycling of Selenium‐Based Optoelectronic Devices

“…[ 1 , 2 , 3 , 4 , 5 ] Amorphous Se (a‐Se) stands as the currently market‐dominant photoconductive material in X‐ray imaging industry, particularly in X‐ray flat‐panel detectors for digital mammography. [ 6 , 7 ] Crystalline Se (c‐Se) is regaining significant attention as a promising absorber for top cells in multi‐junction solar cells and indoor photovoltaics (IPVs) due to its suitable wide bandgap of ≈ 1.9 eV, [ 8 , 9 , 10 , 11 , 12 , 13 ] excellent intrinsic phase and environmental stability to ambient conditions such as humidity, light and oxygen, [ 14 , 15 , 16 ] and nontoxicity as an essential element for humans. [ 17 , 18 , 19 ] In addition, the high piezoelectricity, thermoelectricity, and nonlinear optical responses of Se have also propelled its widespread use in various applications including wearable piezoelectric devices, thermoelectric devices, optical limiters, and field‐effect transistors.…”