Browsing by Author "Chang, Sheng Hsiung"

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Formation and characterization of preferred oriented perovskite thin films on single-crystalline substrates
(2018-06-01)
Chen, Lung-Chien
;
Chen, Cheng-Chiang
;
Chang, Sheng Hsiung
;
Lee, Kuan-Lin
;
Tseng, Zong-Liang
Three single-crystalline (Al2O3, GaN/Al2O3 and InAs) substrates are used to assist the formation of crystallographically preferred oriented CH3NH3PbI3 (MAPbI(3)) thin films. The estimation of the lattice mismatch at the MAPbI(3)/substrate interface and water-droplet contact angle experiments indicate that the formation of a preferred oriented MAPbI(3) thin film is induced by the single-crystalline substrate and is insensitive to the surface wettibility of the substrate. Moreover, the experimental results suggest that the lattice mismatch at the MAPbI(3)/single-crystalline semiconductor interface can strongly influence the photovoltaic performance of tandem solar cells.
Highly efficient solar-heat shield based on the bipolaron-assisted PEDOT:PSS thin film
(2020-08-01)
Thakur, Diksha
;
Wu, Jia-Ren
;
Chandel, Anjali
;
Liu, Shih-Yao
;
Lin, Pei-Chen
We report on an efficient solar-heat shield based on the highly transparent PEDOT:PSS thin film, which significantly reduces the temperature from 38.2 degrees C to 33.5 degrees C. To understand the superior solar-heat shielding ability, the modified PEDOT:PSS thin films were investigated by using the transmittance spectra, Raman scattering spectra, atomic-force microscopic (AFM) images and broadband refractive index spectra. The experimental results show that the molecular structure of the PEDOT chains can be manipulated by varying the Brownian motion of PEDOT polymers in the PEDOT:PSS solutions and the spin rate. The lower Brownian motion of PEDOT polymers and the higher spin rate both can change the molecular structure of the PEDOT chains from bended structures (de-doping states) to linear structures (doping states), which simultaneously increase the near-infrared absorption strength and the visible transparency due to the formation of bipolarons.