An official website of the United States government
Abstract Poly(3,4‐ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) is a popular hole transport material in perovskite solar cells (PSCs). However, the devices with PEDOT:PSS exhibit large open‐circuit voltage (Voc) loss and low efficiency, which is attributed to mismatched energy level alignment and the poor interface of PEDOT:PSS and perovskite. Here, three polymer analogues to polyaniline (PANI), PANI–carbazole (P1), PANI–phenoxazine (P2), and PANI–phenothiazine (P3) are designed with different energy levels to modify the interface between PEDOT:PSS and the perovskite layer and improve the device performance. The effects of the polymers on the device performance are demonstrated by evaluating the work function adjustment, perovskite growth control, and interface modification in MAPbI3‐based PSCs. Low bandgap Sn–Pb‐based PSCs are also fabricated to confirm the effects of the polymers. Three effects are evaluated through the comparison study of PEDOT:PSS‐based organic solar cells and MAPbI3 PSCs based on the PEDOT:PSS modified by P1, P2, and P3. The order of contribution for the three effects is work function adjustment > surface modification > perovskite growth control. MAPbI3 PSCs modified with P2 exhibit a highVocof 1.13 V and a high‐power conversion efficiency of 21.06%. This work provides the fundamental understanding of the interface passivation effects for PEDOT:PSS‐based optoelectronic devices.
more »
« less
Highly Efficient and Stable Perovskite Solar Cells Enabled by Low‐Cost Industrial Organic Pigment Coating
Abstract Surface passivation of perovskite solar cells (PSCs) using a low‐cost industrial organic pigment quinacridone (QA) is presented. The procedure involves solution processing a soluble derivative of QA,N,N‐bis(tert‐butyloxycarbonyl)‐quinacridone (TBOC‐QA), followed by thermal annealing to convert TBOC‐QA into insoluble QA. With halide perovskite thin films coated by QA, PSCs based on methylammonium lead iodide (MAPbI3) showed significantly improved performance with remarkable stability. A PCE of 21.1 % was achieved, which is much higher than 18.9 % recorded for the unmodified devices. The QA coating with exceptional insolubility and hydrophobicity also led to greatly enhanced contact angle from 35.6° for the pristine MAPbI3thin films to 77.2° for QA coated MAPbI3thin films. The stability of QA passivated MAPbI3perovskite thin films and PSCs were significantly enhanced, retaining about 90 % of the initial efficiencies after more than 1000 hours storage under ambient conditions.
more »
« less
- Award ID(s):
- 1912911
- PAR ID:
- 10256921
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Angewandte Chemie International Edition
- Volume:
- 60
- Issue:
- 5
- ISSN:
- 1433-7851
- Page Range / eLocation ID:
- p. 2485-2492
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
Abstract State‐of‐the‐art perovskite solar cells (PSCs) have bandgaps that are invariably larger than 1.45 eV, which limits their theoretically attainable power conversion efficiency. The emergent mixed‐(Pb, Sn) perovskites with bandgaps of 1.2–1.3 eV are ideal for single‐junction solar cells according to the Shockley–Queisser limit, and they have the potential to deliver higher efficiency. Nevertheless, the high chemical activity of Sn(II) in these perovskites makes it extremely challenging to control their physical properties and chemical stability, thereby leading to PSCs with relatively low PCE and stability. In this work, the authors employ the Lewis‐adduct SnF2·3FACl additive in the solution‐processing of ideal‐bandgap halide perovskites (IBHPs), and prepare uniform large‐grain perovskite thin films containing continuously functionalized grain boundaries with the stable SnF2phase. Such Sn(II)‐rich grain‐boundary networks significantly enhance the physical properties and chemical stability of the IBHP thin films. Based on this approach, PSCs with an ideal bandgap of 1.3 eV are fabricated with a promising efficiency of 15.8%, as well as enhanced stability. The concept of Lewis‐adduct‐mediated grain‐boundary functionalization in IBHPs presented here points to a new chemical route for approaching the Shockley–Queisser limit in future stable PSCs.more » « less
-
Abstract Dimethylammonium lead iodide (DMAPbIx) has the potential to address the phase stability issue of inorganic perovskite solar cells (PSCs). In this study, the crystallinity, phase structure, defect states, and crystal growth habits of DMAPbIxare controlled by adjusting thexvalue during synthesis, where N,N‐dimethylacetamide (DMAC) is used as the solvent to regulate perovskite film growth. Furthermore, large‐area CsPbI2.85Br0.15perovskite films with preferred oriented growth are achieved using the optimizedxvalue in DMAPbIxthrough the slot‐die coating method. The inorganic PSCs, with a n‐i‐p structure and the active area of 0.04 cm2, achieve a champion power conversion efficiency (PCE) of 19.82%, with an open‐circuit voltage (Voc) of 1.16 V based on perovskite films formed by slot‐die coating. This work provides important insights into the DMAPbIx‐based method for fabricating high‐quality inorganic perovskite films, and paves the way for large‐area inorganic PSCs fabrication for practical applications.more » « less
-
Conjugated molecules have been typically utilized as either hole or electron extraction layers to boost the device performance of perovskite solar cells (PSCs), formed from three-dimensional (3D) perovskites, due to their high charge carrier mobility and electrical conductivity. However, the passivating role of conjugated molecules in creating two-dimensional (2D) perovskites has rarely been reported. In this study, we report novel conjugated aniline 3-phenyl-2-propen-1-amine (PPA) based 2D perovskites and further demonstrate efficient and stable PSCs containing a (PPA) x (MAPbI 3 ) 1− x /MAPbI 3 bilayer thin film (where MA is CH 3 NH 3 + ). The (PPA) x (MAPbI 3 ) 1− x /MAPbI 3 bilayer thin film possesses superior crystallinity and passivated trap states, resulting in enhanced charge transport and suppressed charge carrier recombination compared to those of a 3D MAPbI 3 thin film. As a result, PSCs containing the (PPA) x (MAPbI 3 ) 1− x /MAPbI 3 bilayer thin film exhibit a power conversion efficiency (PCE) of 21.98%, which is approximately a 25% enhancement compared to that of the MAPbI 3 thin film. Moreover, un-encapsulated PSCs containing the (PPA) x (MAPbI 3 ) 1− x /MAPbI 3 bilayer thin film retain 50% of their initial PCE after 1200 hours in an ambient atmosphere (25 °C, and 30 ± 10 humidity), whereas PSCs with the 3D MAPbI 3 thin film show significant degradation after 100 hours and a degradation of more than 50% of their original PCE after 500 hours. These results demonstrate that the incorporation of conjugated molecules as organic spacer cations to create 2D perovskites on top of 3D perovskites is an effective way to approach high-performance PSCs.more » « less
-
Photovoltaic cells based on metal‐halide perovskites have exceeded the performance of other thin film technologies and rival the performance of devices based on archetypical silicon. Attractively, the perovskite active layer can be processed via a variety of solution‐ and vapor‐based methods. Herein, emphasis is on the use of vapor transport codeposition (VTD) to process efficient n–i–p photovoltaic cells based on methylammonium lead iodide (MAPbI3). VTD utilizes a hot‐walled reactor operated under moderate vacuum in the range of 0.5–10 Torr. The organic and metal‐halide precursors are heated with the resulting vapor transported by a N2carrier gas to a cooled substrate where they condense and react to form a perovskite film. The efficiency of photovoltaic devices based on VTD‐processed MAPbI3is found to be highest in films with excess lead iodide content, with champion devices realizing exceeding 12%.more » « less
