ABSTRACT
With high efficacy for electron-photon conversion under low light, perovskite materials show great potential for indoor solar cell applications to power small electronics for internet of things (IoTs). To match the spectrum of an indoor LED light source, triple cation perovskite composition was varied to adjust band gap values via Cs and Br tuning. However, increased band gaps lead to morphology, phase instability, and defect issues. 10% Cs and 30% Br strike the right balance, leading to low-cost carbon-based devices with the highest power conversion efficiency (PCE) of 31.94% and good stability under low light cycles. With further improvement in device stack and size, functional solar cells with the ultralow hysteresis index (HI) of 0.1 and the highest PCE of 30.09% with an active area of 1 cm2 can be achieved. A module from connecting two such cells in series can simultaneously power humidity and temperature sensors under 1000 lux.
ABSTRACT
A novel waste-based plasticizer derived from modified used palm oil (mUPO) was successfully developed and has been used as a new plasticizer to non-glutinous thermoplastic starch foam to improve their properties. The molecular weight and hydroxyl number of the mUPO was 3150 g/mol and 192.19 mgOH/g, respectively. The effects of mUPO content ranging from 0 to 9 phr were investigated. The results revealed that the optimal mUPO content as an additive was 6 wt%. The addition of mUPO had a direct effect on the mechanical properties and thermal properties. The impact strength increased from 1.30 to 4.55 J/m, while the glass transition temperature (Tg) decreased from 70.83 to 66.50 °C by increasing mUPO from 0 phr to 6 phr in the thermoplastic starch foam. The mUPO, on the other hand, has also the potential to reduce shrinkage from 33.91 to 21.77% and moisture absorption from 5.93 to 1.73% by increasing the content from 0 phr to 6 phr in starch foam. Furthermore, the mUPO helps the forming of the foam structure as measured by SEM, and the mUPO utilization of waste-based material could be a promising green alternative plasticizer for starch components, especially starch foam applications.
ABSTRACT
In this paper we report on the influence of light and oxygen on the stability of CH3 NH3 PbI3 perovskite-based photoactive layers. When exposed to both light and dry air the mp-Al2 O3 /CH3 NH3 PbI3 photoactive layers rapidly decompose yielding methylamine, PbI2 , and I2 as products. We show that this degradation is initiated by the reaction of superoxide (O2 (-) ) with the methylammonium moiety of the perovskite absorber. Fluorescent molecular probe studies indicate that the O2 (-) species is generated by the reaction of photoexcited electrons in the perovskite and molecular oxygen. We show that the yield of O2 (-) generation is significantly reduced when the mp-Al2 O3 film is replaced with an mp-TiO2 electron extraction and transport layer. The present findings suggest that replacing the methylammonium component in CH3 NH3 PbI3 to a species without acid protons could improve tolerance to oxygen and enhance stability.
