26 Jun 13:50
by Yuxuan Fang,
Tian Tian,
Meifang Yang,
Ying Tan,
Jun-Xing Zhong,
Yuhua Huang,
Xudong Wang,
Junlei Tao,
Shaopeng Yang,
Can Zou,
Shuang Yang,
Yong Peng,
Qifan Xue,
Wu‐Qiang Wu
The perovskite precursor chemistry is tailored via solvent engineering, which facilitates homogeneous, nucleation, and rapid crystallization of perovskite films in ambient air without necessity of thermal annealing. The room-temperature processed, blade-coated perovskite solar cells deliver a champion efficiency of 19.16% with negligible hysteresis, improved reproducibility, and extended lifespan.
Abstract
The perovskite solar cells (PSCs) are promising for commercialization and practical application. However, high-quality perovskite films are normally fabricated in inert gas-filled glovebox, followed by thermal annealing, which is energy-consuming and thus not cost-effective. In this study, a simple manufacturing strategy is demonstrated to fabricate the highly-crystalline perovskite films in ambient air (a relative humidity of over ≈50%) at room temperature via blade-coating without the subsequent thermal–annealing. The perovskite precursor chemistry is tailored by solvent engineering via employing 2-methoxyethanol, which can strongly coordinate with ammonium halide species, thus forming highly uniform small-sized colloids and facilitating the homogeneous nucleation and rapid crystallization of perovskite films even at room temperature. The resultant PSCs fabricated with ambient-processed, annealing-free MAPbI3 perovskite films exhibit a champion efficiency up to 19.16% with negligible hysteresis and improved reproducibility, which is on par with the high-temperature annealed counterparts fabricated in N2, and represented one of the highest reported efficiencies for the room-temperature processed PSCs in ambient air. The unencapsulated devices show extended lifespan over 1000 h with nearly no efficiency loss.
21 Nov 12:55
by Tong Xing,
Chenxi Zhu,
Qingfeng Song,
Hui Huang,
Jie Xiao,
Dudi Ren,
Moji Shi,
Pengfei Qiu,
Xun Shi,
Fangfang Xu,
Lidong Chen
Via using large mass and strain field fluctuations as indicators for low lattice thermal conductivity, the combination of (Mg, Bi) is screened as effective dopants in GeTe. As a result of the optimized carrier concentration, increased band convergence, and lowered lattice thermal conductivity, Ge0.9Mg0.04Bi0.06Te shows a superhigh zT of ≈2.5 at 700 K.
Abstract
High‐efficiency thermoelectric (TE) technology is determined by the performance of TE materials. Doping is a routine approach in TEs to achieve optimized electrical properties and lowered thermal conductivity. However, how to choose appropriate dopants with desirable solution content to realize high TE figure‐of‐merit (zT) is very tough work. In this study, via the use of large mass and strain field fluctuations as indicators for low lattice thermal conductivity, the combination of (Mg, Bi) in GeTe is screened as very effective dopants for potentially high zTs. In experiments, a series of (Mg, Bi) co‐doped GeTe compounds are prepared and the electrical and thermal transport properties are systematically investigated. Ultralow lattice thermal conductivity, about 0.3 W m−1 K−1 at 600 K, is obtained in Ge0.9Mg0.04Bi0.06Te due to the introduced large mass and strain field fluctuations by (Mg, Bi) co‐doping. In addition, (Mg, Bi) co‐doping can introduce extra electrons for optimal carrier concentration and diminish the energy offset at the top of the valence band for high density‐of‐states effective mass. Via these synthetic effects, a superhigh zT of ≈2.5 at 700 K is achieved for Ge0.9Mg0.04Bi0.06Te. This study sheds light on the rational design of effective dopants in other TE materials.
27 Mar 12:10
by Pushkar Dasika,
Debadarshini Samantaray,
Krishna Murali,
Nithin Abraham,
Kenji Watanbe,
Takashi Taniguchi,
N Ravishankar,
Kausik Majumdar
A high‐performance, dual‐gated, p‐type, junctionless transistor is demonstrated using tellurium nanowire as the channel. A unique combination of contact‐barrier‐free hole injection, high hole mobility (570 cm2 V−1 s−1 at 270 K), dangling‐bond‐free interface between the nanowire, and hBN gate‐dielectric and the dual‐gated operation helps to achieve an on‐off ratio of 2 × 104 with a high on‐current of 216 mA mm−1. The findings have intriguing prospects for next‐generation electronics.
Abstract
The gate‐all‐around nanowire transistor, due to its extremely tight electrostatic control and vertical integration capability, is a highly promising candidate for sub‐5 nm technology nodes. In particular, the junctionless nanowire transistors are highly scalable with reduced variability due to avoidance of steep source/drain junction formation by ion implantation. Here a dual‐gated junctionless nanowire p‐type field effect transistor is demonstrated using tellurium nanowire as the channel. The dangling‐bond‐free surface due to the unique helical crystal structure of the nanowire, coupled with an integration of dangling‐bond‐free, high quality hBN gate dielectric, allows for a phonon‐limited field effect hole mobility of 570 cm2 V−1 s−1 at 270 K, which is well above state‐of‐the‐art strained Si hole mobility. By lowering the temperature, the mobility increases to 1390 cm2 V−1 s−1 and becomes primarily limited by Coulomb scattering. The combination of an electron affinity of ≈4 eV and a small bandgap of tellurium provides zero Schottky barrier height for hole injection at the metal‐contact interface, which is remarkable for reduction of contact resistance in a highly scaled transistor. Exploiting these properties, coupled with the dual‐gated operation, we achieve a high drive current of 216 μA μm−1 while maintaining an on‐off ratio in excess of 2 × 104. The findings have intriguing prospects for alternate channel material based next‐generation electronics.
04 Aug 17:07
by Jakob Bombsch*†, Enrico Avancini‡§, Romain Carron‡, Evelyn Handick†, Raul Garcia-Diez†, Claudia Hartmann†, Roberto Fe´lix†, Shigenori Ueda??, Regan G. Wilks†#, and Marcus Ba¨r*†#??
ACS Applied Materials & Interfaces
DOI: 10.1021/acsami.0c08794
20 Aug 02:06
by Xiangchuan Meng,
Lin Zhang,
Yuanpeng Xie,
Xiaotian Hu,
Zhi Xing,
Zengqi Huang,
Cong Liu,
Licheng Tan,
Weihua Zhou,
Yanming Sun,
Wei Ma,
Yiwang Chen
A general approach for lab‐to‐manufacturing translation is developed to achieve high‐performance flexible organic solar modules without obvious efficiency loss. The shear impulse during the coating/printing process is applied to control the morphology evolution of the bulk heterojunction layer for both fullerene and nonfullerene acceptor systems. A quantitative transformation factor of shear impulse between slot‐die printing and spin‐coating is detected.
Abstract
The blossoming of organic solar cells (OSCs) has triggered enormous commercial applications, due to their high‐efficiency, light weight, and flexibility. However, the lab‐to‐manufacturing translation of the praisable performance from lab‐scale devices to industrial‐scale modules is still the Achilles' heel of OSCs. In fact, it is urgent to explore the mechanism of morphological evolution in the bulk heterojunction (BHJ) with different coating/printing methods. Here, a general approach to upscale flexible organic photovoltaics to module scale without obvious efficiency loss is demonstrated. The shear impulse during the coating/printing process is first applied to control the morphology evolution of the BHJ layer for both fullerene and nonfullerene acceptor systems. A quantitative transformation factor of shear impulse between slot‐die printing and spin‐coating is detected. Compelling results of morphological evolution, molecular stacking, and coarse‐grained molecular simulation verify the validity of the impulse translation. Accordingly, the efficiency of flexible devices via slot‐die printing achieves 9.10% for PTB7‐Th:PC71BM and 9.77% for PBDB‐T:ITIC based on 1.04 cm2 . Furthermore, 15 cm2 flexible modules with effective efficiency up to 7.58% (PTB7‐Th:PC71BM) and 8.90% (PBDB‐T:ITIC) are demonstrated with satisfying mechanical flexibility and operating stability. More importantly, this work outlines the shear impulse translation for organic printing electronics.
Open Access
