Design, Frabrication And Solar Application Of Light Trapping Structure Of Chalcogenide Semiconductors

Light absorption is one of crucial factors which dominates the power conversion efficiency of solar energy devices. For most of the common semiconductors, their relatively high refractive index always cause optical losses, and it is still a big challenge to improve light absorption. Herein, we present some solutions to the above problem, where the nanoflake arrays(NFAs) and inverse opals structures(IOS) are demonstrated as effective light absorbers for efficient photon-electron-conversion(PEC).1. The NFAs with appropriate flake size and orientation were demonstrated as excellent absorbers with light absorption as high as 95%, being superior to commonly used thin film or inverse opal order porous structures. Further investigates revesl that the enhancement of light absorption can be attributed to the mlti-reflection effect between the flakes. The high light trapping effect of NFAs appears in various materials, such as CdS, CdSe, Cu2ZnSnS4 and even metal Cd NFAs.2. The NFAs were demonstrated as a scaffold to load organic absorber, and enable the thin organic absorber(the thickness is ~15 nm) achieve extraordinarily high absorption efficiency(95%). Correspondingly, the hybrid solar cell consisting of CdS NFAs and P3 HT can yield a short-circuit photocurrent of 4.4 mA cm-2, ten times of the counterpart device consisting of planar CdS film and P3 HT. By further investigate, we get clear that both the CdS section and P3 HT section contribute to the total photocurrent enhancement.3. A novel CdS/P3 HT hollow HSC was designed with(1) NFAs network,(2) CdS/P3 HT core-shell geometry and(3) hollow structure. Benefiting from the effective utilization of the incident light and balancing the carries transfer, the new HSC exhibits a high photocurrent density of 3.4 mA cm-2 and a photoelectric conversion efficiency of 0.52 %, which are much higher than the traditional CdS NFAs/ infiltrated P3 HT HSC and CdS film/P3 HT planar HSC. This cell-structure is also integrated into the CdSe NFAs/ P3 HT HSC, and a similar photocurrent increasement was observed.4. A novel IOS CdS electrode was prepared. Benefiting from the appropriate wall thickness and porous architecture, the new electrode can effectively increase the light absorption as well as facilitate the hole transfer. As a result, a high photocurrent density of 3.1 m A cm-2 was obtained, which value is 3.1 times as high as the thin film’s. Moreover, the IOS electroce also exhibits a high photocurrent stability during 3 h illumination. An additional CdSe layer was successfully coated onto the CdS IOS, as a result, the electrode composing with CdS and CdSe exhibits a much higher photocurrent up to 10.5 mA cm-2.