Pushing efficiency limits for semitransparent perovskite solar cells

Abstract

While perovskite-based semitransparent solar cells deliver competitive levels of transparency and efficiency to be envisioned for urban infrastructures, the complexity and sensitivity of their processing conditions remain challenging. Here, we introduce two robust protocols for the processing of sub-100 nm perovskite films, allowing fine-tuning of the active layer without compromising the crystallinity and quality of the semiconductor. Specifically, we demonstrate that a method based on solvent-induced crystallization with a rapid drying step affords perovskite solar cells with 37% average visible transmittance (AVT) and 7.8% PCE. This process enhances crystallization with a preferential phase orientation presumably at the interface, yielding a high fill factor of 72.3%. The second method is based on a solvent-solvent extraction protocol, enabling active layer films as thin as 40 nm and featuring room-temperature crystallization in an ambient environment on a few second time span. As a result, we demonstrate a maximum AVT of 46% with an efficiency of 3.6%, which is the highest combination of efficiency and transparency for a full device stack to date. By combining the two methods presented here we cover a broad range of thicknesses vs. transparency values and confirm that solvent-induced crystallization represents a powerful processing strategy toward high-efficiency semitransparent solar cells. Optical simulations support our experimental findings and provide a global perspective of the opportunities and limitations of semitransparent perovskite photovoltaic devices.

Efficient Planar Perovskite Solar Cells via a Sputtered Cathode

“…While for the counter electrodes, the carbon materials or silver nanowires have been deposited via a wet‐chemistry printing method. However, the carbon materials have low conductivity, while the silver nanowires are readily react with the halides to form silver halides .…”

Progress in Scalable Coating and Roll‐to‐Roll Compatible Printing Processes of Perovskite Solar Cells toward Realization of Commercialization

“…As one of promising candidates, silver nanowires (AgNWs) have been employed for printable metal back electrode of PeSCs . The AgNWs dispersion solution was deposited via solution processes, such as spin coating or spray coating, as the top electrode, and the final devices were semi‐transparent with a reasonable cell performance under both side illuminations.…”

Metal‐Nanowire‐Electrode‐Based Perovskite Solar Cells: Challenging Issues and New Opportunities

“…[102][103][104][105][106] However, in this approach, the vacuum deposition process is indispensably required for preparing thin metal films and the presence of metallic layers causes inevitable decreases in transmittance. [101] Therefore, a variety of top electrodes including AZO, [107] ITO, [108][109][110] In 2 O 3 :H, [111] PEDOT:PSS, [112,113] graphene, [114] CNT, [115] and MeNWs [87][88][89][91][92][93][94][95]97,[116][117][118][119] have been investigated for fabricating high-performance semi-transparent PSCs. When they are compared in the plot presenting the interdependency between AVT and PCE (Figure 3), it can be noticed that the semi-transparent cells employing AgNW-network top electrodes are in the top-right area, where highly transparent and high-functioning cells are positioned.…”

“…(ii) the use of an inverted structure with the incorporation of both PEDOT:PSS and PC 60 BM layers helped avoid the transmittance regression in the Spiro-OMeTAD layer. [117] Since the first demonstration, slightly improved semitransparent PSCs [89,91,93,117] have been reported with an identical stacked structure of ITO/PEDOT:PSS/OMHP/PCBM/ZnO/ AgNW, and the device performance enhancement was attributable to subtle variations in the OMHP layer deposition method [91] and an optimized ZnO film morphology. [89] Semi-transparent PSCs with AgNW-network electrodes have been applied to device architectures of tandem cells.…”

“…[164,165] Owing to this issue, the currently reported studies are, in general, devoid of fused-junction formation steps, even if the device performance could be restricted with a limited sheet resistance of electrodes. [87][88][89]91,92,94] As a first trial to resolve this issue, a physical method of forming a mechanical pressure-mediated electrical junction was suggested in order to improve the sheet resistance of AgNW-network electrodes without triggering a thermally driven phase decomposition of OMHP layers. [166] Indeed, with the aforementioned ball-bearing method, the transferred AgNW-networks showed an improved sheet resistance, 2 Ω sq −1 , as compared to 12.4 Ω sq −1 for a pristine sample, probably due to the facile junction formation between AgNWs.…”