shuhui

In-situ cross-linking strategy for efficient and operationally stable methylammoniun lead iodide solar cells

In-situ cross-linking strategy for efficient and operationally stable methylammoniun lead iodide solar cells, Published online: 18 September 2018; doi:10.1038/s41467-018-06204-2

Graphdiyne‐ZnO composite material is prepared via a simple method and studied in detail. Zn and O atoms can coordinate bonding with graphdiyne, thus forming the CZn bond and CO bond, respectively, which improves the morphology and electrical conductivity of the interfacial layer. Polymer solar cells based on the nanocomposites obtain an enhanced power conversion efficiency of 11.2% compared with the devices with ZnO‐only (10%).

Graphdiyne‐ZnO (GDZO) composite material is prepared via a simple method and studied in detail for the first time. The transmission electron microscopy, Raman spectroscopy and X‐ray photoelectron spectroscopy (XPS) analyses confirm the formation of an adduct between GD and ZnO. Then the interaction between ZnO and GD is further investigated by first‐principles calculations. It is found that the Zn and O atom can coordinate bonding with GD, thus forming the CZn bond and CO bond, respectively. Polymer solar cells are fabricated based on the nanocomposites for the first time and an enhanced power conversion efficiency of 11.2%, compared with the devices with ZnO‐only (10%), is obtained. Simultaneously, the resultant devices show better stability, whether in glove box or in atmosphere, with humidity of 90%. The investigation of exciton generation rate, ideal current‐voltage model, and impedance spectra verify that the introduction of GDZO not only accelerates electron transfer but also reduces charge recombination occurring at the interface. The results indicate that GDZO is a promising electron transport material to enhance solar cell performance and presents a large potential for optoelectronic applications as well.

Interface passivation of ultrathin Cu(In,Ga)Se₂ solar cells is important to achieve enhanced performance of solar cells. The potential of SiO₂ as a passivation layer and the implementation of nano‐patterning (production of sub‐micrometer contacts) on SiO₂ by optical lithography is investigated. Co‐relation between the dimensions of sub‐micrometer contacts and its implications on performance of the ultrathin passivated solar cells is thoroughly investigated.

Ultrathin Cu(In,Ga)Se₂ solar cells are a promising way to reduce costs and to increase the electrical performance of thin film solar cells. An optical lithography process that can produce sub‐micrometer contacts in a SiO₂ passivation layer at the CIGS rear contact is developed in this work. Furthermore, an optimization of the patterning dimensions reveals constrains over the features sizes. High passivation areas of the rear contact are needed to passivate the CIGS interface so that high performing solar cells can be obtained. However, these dimensions should not be achieved by using long distances between the contacts as they lead to poor electrical performance due to poor carrier extraction. This study expands the choice of passivation materials already known for ultrathin solar cells and its fabrication techniques.

A high quality CsPbI₂Br perovskite film is prepared by a Lewis base adduct‐promoted growth process. A CsPbI₂Br perovskite solar cell (PSC) with a power conversion efficiency (PCE) of 13.54% is obtained at low temperature (120 °C). In addition, the method enables fabrication of flexible CsPbI₂Br PSC with PCE as high as 11.73%.

Abstract

All‐inorganic CsPbX₃‐based perovskites, such as CsPbI₂Br, show much better thermal and illumination stability than their organic–inorganic hybrid counterparts. However, fabrication of high‐quality CsPbI₂Br perovskite film normally requires annealing at a high temperature (>250 °C) that is not compatible with the plastic substrate. In this work, a Lewis base adduct‐promoted growth process that makes it possible to fabricate high quality CsPbI₂Br perovskite films at low temperature is promoted. The mechanism is attributed to synthesized dimethyl sulfoxide (DMSO) adducts which allow a low activation energy route to form CsPbI₂Br perovskite films during the thermal annealing treatment. A power conversion efficiency (PCE) of 13.54% is achieved. As far as it is known, this is the highest efficiency for the CsPbI₂Br solar cells fabricated at low temperature (120 °C). In addition, the method enables fabrication of flexible CsPbI₂Br PSCs with PCE as high as 11.73%. Surprisingly, the bare devices without any encapsulation maintain 70% of their original PCEs after being stored in ambient air for 700 h. This work provides an approach for preparing other high performance CsPbX₃‐based perovskite solar cells (PSCs) at low temperature, particularly for flexible ones.

A pseudo‐3D CH₃CH₂CH₂NH₃PbI₃ perovskite film is deposited by a scalable dip‐coating technique with high surface coverage, and then conversed to a high‐quality 3D CH₃NH₃PbI₃ perovskite film via an organic‐cation displacement approach. With the MAPbI₃ film as the light absorber, planar perovskite solar cells are fabricated, affording stabilized power conversion efficiencies of 19.27% and 15.68% for 0.09 and 5.02 cm² devices, respectively.

Abstract

Methylammonium iodide (MAI) and lead iodide (PbI₂) have been extensively employed as precursors for solution‐processed MAPbI₃ perovskite solar cells (PSCs). However, the MAPbI₃ perovskite films directly deposited from the precursor solutions, usually suffer from poor surface coverage due to uncontrolled nucleation and crystal growth of the perovskite during the film formation, resulting in low photovoltaic conversion efficiency and poor reproducibility. Herein, propylammonium iodide and PbI₂ are employed as precursors for solution deposition of propylammonium lead iodide (PAPbI₃) perovskite film. It is found that the precursors have good film formability, enabling the deposition of a large‐area and homogeneous PAPbI₃ perovskite film by a scalable dip‐coating technique. The dip‐coated PAPbI₃ film is then subjected to an organic‐cation displacement reaction, resulting in MAPbI₃ film with high surface coverage and crystallinity. With the MAPbI₃ film as the light absorber, planar PSCs are fabricated, and stabilized power conversion efficiencies of 19.27% and 15.68% can be achieved for the devices with active areas of 0.09 and 5.02 cm², respectively. The technology reported here provides a robust and efficient approach to fabricate large‐area and high‐efficiency perovskite cells for practical application.