AlGaN-based light-emitting diodes(LEDs)on offcut substrates enhance radiative emission via forming carrier localization centers in multiple quantum wells(MQWs).This study introduces the carrier transport barrier conce...AlGaN-based light-emitting diodes(LEDs)on offcut substrates enhance radiative emission via forming carrier localization centers in multiple quantum wells(MQWs).This study introduces the carrier transport barrier concept,accessing its impact on the quantum efficiency of LEDs grown on different offcut sapphire substrates.A significantly enhanced internal quantum efficiency(IQE)of 83.1%is obtained from MQWs on the 1°offcut sapphire,almost twice that of the controlled 0.2°offcut sample.Yet,1°offcut LEDs have higher turn-on voltage and weaker electroluminescence than 0.2°ones.Theoretical calculations demonstrate the existence of a potential barrier on the current path around the step-induced Ga-rich stripes.Ga-rich stripes reduce the turn-on voltage but restrict sufficient driving current,impacting LED performance.展开更多
The efficiency of rigid perovskite/silicon tandem solar cells has reached 33.9%.However,there has been no report on flexible perovskite/silicon tandem solar cells due to the challenge of overcoming the poor light abso...The efficiency of rigid perovskite/silicon tandem solar cells has reached 33.9%.However,there has been no report on flexible perovskite/silicon tandem solar cells due to the challenge of overcoming the poor light absorption of ultrathin silicon bottom cells while maintaining their mechanical flexibility.Herein,we report the first demonstration of the perovskite/silicon tandem solar cell based on flexible ultrathin silicon.We show that reducing the wafer thicknesses and feature sizes of the light-trapping textures can significantly improve the flexibility of silicon without sacrificing light utilization.In addition,the capping of the perovskite top cells can further improve the device's mechanical durability by shifting the neutral plane toward the silicon surface that is prone to fracture.Finally,the resulting ultrathin(~30μm)flexible perovskite/silicon tandem solar cell achieves a certified stabilized efficiency of 22.8%with an extremely high power-to-weight ratio of 3.12 W g^(-1).Moreover,the flexible tandems exhibit remarkable bending durability,maintaining 98.2%of their initial performance after 3000 bending cycles at a radius of only 1 cm.展开更多
基金supported by the National Natural Science Foundation of China(No.62104233)the Natural Science Foundation of Ningbo(No.2022J298)+1 种基金the Zhejiang Provincial Natural Science Foundation(No.LQ21F040004)the Ningbo Innovation 2025 Major Project(No.2021Z082)。
文摘AlGaN-based light-emitting diodes(LEDs)on offcut substrates enhance radiative emission via forming carrier localization centers in multiple quantum wells(MQWs).This study introduces the carrier transport barrier concept,accessing its impact on the quantum efficiency of LEDs grown on different offcut sapphire substrates.A significantly enhanced internal quantum efficiency(IQE)of 83.1%is obtained from MQWs on the 1°offcut sapphire,almost twice that of the controlled 0.2°offcut sample.Yet,1°offcut LEDs have higher turn-on voltage and weaker electroluminescence than 0.2°ones.Theoretical calculations demonstrate the existence of a potential barrier on the current path around the step-induced Ga-rich stripes.Ga-rich stripes reduce the turn-on voltage but restrict sufficient driving current,impacting LED performance.
基金supported by the Key Research and Development Program of Ningbo(2023Z151)the Key Research and Development Program of Zhejiang Province(2022C01215,2024C01092)+4 种基金the China Postdoctoral Science Foundation(2023M743620)the Joint Funds of the Zhejiang Provincial Natural Science Foundation of China(LBMHD24E020002)the Zhejiang Provincial Natural Science Foundation of China(LY24F040003)the National Key Research and Development of China(2018YFB1500103)the National Natural Science Foundation of China(62204245,U23A200098)。
文摘The efficiency of rigid perovskite/silicon tandem solar cells has reached 33.9%.However,there has been no report on flexible perovskite/silicon tandem solar cells due to the challenge of overcoming the poor light absorption of ultrathin silicon bottom cells while maintaining their mechanical flexibility.Herein,we report the first demonstration of the perovskite/silicon tandem solar cell based on flexible ultrathin silicon.We show that reducing the wafer thicknesses and feature sizes of the light-trapping textures can significantly improve the flexibility of silicon without sacrificing light utilization.In addition,the capping of the perovskite top cells can further improve the device's mechanical durability by shifting the neutral plane toward the silicon surface that is prone to fracture.Finally,the resulting ultrathin(~30μm)flexible perovskite/silicon tandem solar cell achieves a certified stabilized efficiency of 22.8%with an extremely high power-to-weight ratio of 3.12 W g^(-1).Moreover,the flexible tandems exhibit remarkable bending durability,maintaining 98.2%of their initial performance after 3000 bending cycles at a radius of only 1 cm.
