| Popis: |
In the past 10 years, perovskite solar cells (PSCs) have drawn great attention in both academic and industrial sectors. Over 25.5% power conversion efficiency (PCE) has been reported from PSCs by three-dimensional (3D) methylammonium lead iodide (CH3NH3PbI3 or MAPbI3). However, the previous studies have indicated that PSCs exhibited poor stability. Thus, to commercialize PSCs, the development of efficient and stable PSCs is required. In this study, we reported two approaches to develop efficient and stable PSCs. One was to develop novel all-inorganic perovskites, where Pb2+ was partially heterovalently substituted Nd3+. Another was to develop PSCs with a bulk heterojunction (BHJ) device structure. In the first approach, it was found that the CsPbI2Br:xNd3+ thin films possess enhanced charge carrier mobilities, superior crystallinity, and enlarged crystal sizes, but with enlarged optical bandgaps. As a result, PSCs by the CsPbI2Br:xNd3+ thin films exhibit more than 20% enhanced PCEs and boosted stability compared to those by pristine CsPbI2Br thin film. To further boost the device performance of PSCs, solution-processed 4-lithium styrenesulfonic acid/styrene copolymer (LiSPS) is utilized as the passivation layer. PSCs by the CsPbI2Br:xNd3+/LiSPS bilayer thin film possesses reduced charge extraction lifetime and suppressed charge carrier recombination, resulting in 17.05% PCE and dramatically boosted stability compared to that without the LiSPS passivation layer. All these results indicate that we develop a facile way to approach high-performance PSCs by all-inorganic perovskite materials.In the second approach, we found that all-inorganic perovskite incorporated with low bandgap conjugated polymers, forming BHJ composite thin film possesses balanced and enhanced charge mobilities, superior film morphology with enlarged crystal sizes, and suppressed trap density As a result, BHJ PSCs exhibited a 21.08% PCEs, which is more than 16% enhancement compared to that without incorporated with low bandgap conjugated polymers. Moreover, BHJ PSCs possess suppressed photocurrent hysteresis and enhanced device stability. All these results demonstrate that the development of BHJ PSCs is one of the facil ways to approach high-performance PSCs. |
