Roll-to-roll fabrication of large scale and regular arrays of three-dimensional nanospikes for high efficiency and flexible photovoltaics

TLDR

Three‑dimensional nanostructures enhance photovoltaic performance by improving photon capture, yet scalable, robust, and flexible fabrication of regular 3‑D nanostructures remains a challenge. The study aims to establish rational design guidelines for 3‑D nanostructured solar cells that balance electrical and optical performance. Regular arrays of 3‑D nanospikes were fabricated on flexible aluminum foil using a roll‑to‑roll compatible process, with precisely controlled geometry and periodicity enabling systematic investigation of geometry‑dependent optical and electrical performance through experiments and modeling. Amorphous‑Si photovoltaic devices on nanospike arrays achieved a 43 % efficiency increase over planar counterparts, and large‑scale flexible nanospike solar cells were demonstrated, providing design rules and a practical fabrication route with potential industry impact.

Abstract

Three-dimensional (3-D) nanostructures have demonstrated enticing potency to boost performance of photovoltaic devices primarily owning to the improved photon capturing capability. Nevertheless, cost-effective and scalable fabrication of regular 3-D nanostructures with decent robustness and flexibility still remains as a challenging task. Meanwhile, establishing rational design guidelines for 3-D nanostructured solar cells with the balanced electrical and optical performance are of paramount importance and in urgent need. Herein, regular arrays of 3-D nanospikes (NSPs) were fabricated on flexible aluminum foil with a roll-to-roll compatible process. The NSPs have precisely controlled geometry and periodicity which allow systematic investigation on geometry dependent optical and electrical performance of the devices with experiments and modeling. Intriguingly, it has been discovered that the efficiency of an amorphous-Si (a-Si) photovoltaic device fabricated on NSPs can be improved by 43%, as compared to its planar counterpart, in an optimal case. Furthermore, large scale flexible NSP solar cell devices have been fabricated and demonstrated. These results not only have shed light on the design rules of high performance nanostructured solar cells, but also demonstrated a highly practical process to fabricate efficient solar panels with 3-D nanostructures, thus may have immediate impact on thin film photovoltaic industry.