Research into organic-inorganic metal halide perovskite solar cells has swiftly gained momentum since the seminal work initiated by Kojima et al. in 2009, and already has delivered impressive accredited power conversion efficiency of over 17.9% within 5 years. In much previously reported research, the I-V characteristics was found to vary to a great extent with sweeping direction, which is known as I-V hysteresis. Further investigations have identified that the I-V hysteresis is also related to scanning speed, starting voltage and light soaking. We correlate such a phenomenon to different device structures and several possible causes were analyzed herein. A reliable test to obtain valid power conversion efficiency, which is to hold the device under a maximum power voltage is recommended for future research regarding this newly emerged technology.
Abstract-Heat-sealing BOPP films are used widely as commercial packages in recent years. However, nowadays there are some obstacles in heat-sealing BOPP films producing, for example the heat sealing strength is relatively low, which makes heat-sealing BOPP films not satisfy the increasing demands of the modern packagings with highperformances. Therefore, an effective reseach on the relationship of the performences of BOPP film and its physical parameters is in great need. In this paper, we tested various performance indicators of heat-sealing BOPP films with different surface coating thickness. The results showed that heat-sealing strength and haze of BOPP films significantly changed with different coating thickness, while the friction coefficient did not change obviously.
Deep level capacitance transient spectroscopy was used to obtain the energy level and the capture characteristics of InAs self-assembled quantum dots embedded in GaAs. A specially designed structure was used for the DLTS measurement for enhanced resolution. This structure allows us to detect capacitance relaxation signal from a single layer of quantum dots and to separate this signal from those of the DX centers inside the structure. The DLTS spectra with different filling pulses and different rate windows provide clear information on the energy level and the capture characteristics of the quantum dots.
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