Metal halide perovskites (MHPs) have emerged as a frontrunner semiconductor technology for application in third generation photovoltaics while simultaneously making significant strides in other areas ...of optoelectronics. Photodetectors are one of the latest additions in an expanding list of applications of this fascinating family of materials. The extensive range of possible inorganic and hybrid perovskites coupled with their processing versatility and ability to convert external stimuli into easily measurable optical/electrical signals makes them an auspicious sensing element even for the high‐energy domain of the electromagnetic spectrum. Key to this is the ability of MHPs to accommodate heavy elements while being able to form large, high‐quality crystals and polycrystalline layers, making them one of the most promising emerging X‐ray and γ‐ray detector technologies. Here, the fundamental principles of high‐energy radiation detection are reviewed with emphasis on recent progress in the emerging and fascinating field of metal halide perovskite‐based X‐ray and γ‐ray detectors. The review starts with a discussion of the basic principles of high‐energy radiation detection with focus on key performance metrics followed by a comprehensive summary of the recent progress in the field of perovskite‐based detectors. The article concludes with a discussion of the remaining challenges and future perspectives.
Metal halide perovskites have emerged as a promising family of electronic materials for application in optoelectronics. One area where scientific interest in these materials has been intensifying is high‐energy radiation detection. This review discusses the progress in the application of metal halide perovskites for direct & indirect X‐ray and Gamma‐ray detection.
Reducing the thickness of an amorphous conductive indium tin oxide layer down to a few nanometres has enabled the realization of 40-nm-long channel transistors with remarkable operating ...characteristics.
Self‐assembled monolayers (SAMs) based on Br‐2PACz (2‐(3,6‐dibromo‐9H‐carbazol‐9‐yl)ethylphosphonic acid) 2PACz (2‐(9H‐Carbazol‐9‐yl)ethylphosphonic acid) and MeO‐2PACz ...(2‐(3,6‐dimethoxy‐9H‐carbazol‐9‐yl)ethylphosphonic acid) molecules were investigated as hole‐extracting interlayers in organic photovoltaics (OPVs). The highest occupied molecular orbital (HOMO) energies of these SAMs were measured at −6.01 and −5.30 eV for Br‐2PACz and MeO‐2PACz, respectively, and found to induce significant changes in the work function (WF) of indium‐tin‐oxide (ITO) electrodes upon chemical functionalization. OPV cells based on PM6 (poly(2,6‐(4,8‐bis(5‐(2‐ethylhexyl‐3‐fluoro)thiophen‐2‐yl)‐benzo1,2‐b:4,5‐b’dithiophene))‐alt‐(5,5‐(1’,3’‐di‐2‐thienyl‐5’,7’‐bis(2‐ethylhexyl)benzo1’,2’‐c:4’,5’‐c’dithiophene‐4,8‐dione)) : BTP‐eC9 : PC71BM (6,6‐phenyl‐C71‐butyric acid methyl ester) using ITO/Br‐2PACz anodes exhibited a maximum power conversion efficiency (PCE) of 18.4 %, outperforming devices with ITO/MeO‐2PACz (14.5 %) and ITO/poly(3,4‐ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT : PSS) (17.5 %). The higher PCE was found to originate from the much higher WF of ITO/Br‐2PACz (−5.81 eV) compared to ITO/MeO‐2PACz (4.58 eV) and ITO/PEDOT : PSS (4.9 eV), resulting in lower interface resistance, improved hole transport/extraction, lower trap‐assisted recombination, and longer carrier lifetimes. Importantly, the ITO/Br‐2PACz electrode was chemically stable, and after removal of the SAM it could be recycled and reused to construct fresh OPVs with equally impressive performance.
Super SAM: Two self‐assembled monolayers (SAMs; Br‐2PACz and MeO‐2PACz) are investigated as hole‐extracting interlayer in organic photovoltaics and compared against the widely used PEDOT : PSS. Cells based on the ternary bulk‐heterojunction blend PM6 : BTP‐eC9 : PC71BM and ITO/Br‐2PACz as the anode exhibit the highest power conversion efficiency of 18.4 %, outperforming devices with ITO/MeO‐2PACz (14.5 %) and even ITO/PEDOT : PSS (17.5 %).
Flexible electronics have seen extensive research over the past years due to their potential stretchability and adaptability to non‐flat surfaces. They are key to realizing low‐power sensors and ...circuits for wearable electronics and Internet of Things (IoT) applications. Semiconducting metal‐oxides are a prime candidate for implementing flexible electronics as their conformal deposition methods lend themselves to the idiosyncrasies of non‐rigid substrates. They are also a major component for the development of resistive memories (memristors) and as such their monolithic integration with thin film electronics has the potential to lead to novel all‐metal‐oxide devices combining memory and computing on a single node. This review focuses on exploring the recent advances across all these fronts starting from types of suitable substrates and their mechanical properties, different types of fabrication methods for thin film transistors and memristors applicable to flexible substrates (vacuum‐ or solution‐based), applications and comparison with rigid substrates while additionally delving into matters associated with their monolithic integration.
Metal oxides play an increasingly important role in flexible electronics that aim to deliver emerging applications such as novel computing systems, integrating thin‐film transistors and resistive memories (memristors) in crossbars arrays. Due to the low temperature processing in metal oxides, mechanical flexibility has been increasingly studied in related devices, and therefore it is covered in this review.
Over the past few decades, significant progress has been made in the field of photonic processing of electronic materials using a variety of light sources. Several of these technologies have now been ...exploited in conjunction with emerging electronic materials as alternatives to conventional high‐temperature thermal annealing, offering rapid manufacturing times and compatibility with temperature‐sensitive substrate materials among other potential advantages. Herein, recent advances in photonic processing paradigms of metal‐oxide thin‐film transistors (TFTs) are presented with particular emphasis on the use of various light source technologies for the photochemical and thermochemical conversion of precursor materials or postdeposition treatment of metal oxides and their application in thin‐film electronics. The pros and cons of the different technologies are discussed in light of recent developments and prospective research in the field of modern large‐area electronics is highlighted.
Photonic (post)processing of metal‐oxide materials and transistors can offer important advantages over traditional techniques that are of particular relevance to the scalable manufacturing of emerging forms of large‐area electronics. Here, the critical aspects of photonic processing of metal‐oxide electronics are reviewed with emphasis on the pros and cons of the various technologies available to date.
In this communication, we report the synthesis of a novel diketopyrrolopyrrole–diketopyrrolopyrrole (DPP–DPP)-based conjugated copolymer and its application in high-mobility organic field-effect ...transistors. Copolymerization of DPP with DPP yields a copolymer with exceptional properties such as extended absorption characteristics (up to ∼1100 nm) and field-effect electron mobility values of >1 cm2 V–1 s–1. The synthesis of this novel DPP–DPP copolymer in combination with the demonstration of transistors with extremely high electron mobility makes this work an important step toward a new family of DPP–DPP copolymers for application in the general area of organic optoelectronics.
All‐inorganic CsPbI3 holds promise for efficient tandem solar cells, but reported fabrication techniques are not transferrable to scalable manufacturing methods. Herein, printable CsPbI3 solar cells ...are reported, in which the charge transporting layers and photoactive layer are deposited by fast blade‐coating at a low temperature (≤100 °C) in ambient conditions. High‐quality CsPbI3 films are grown via introducing a low concentration of the multifunctional molecular additive Zn(C6F5)2, which reconciles the conflict between air‐flow‐assisted fast drying and low‐quality film including energy misalignment and trap formation. Material analysis reveals a preferential accumulation of the additive close to the perovskite/SnO2 interface and strong chemisorption on the perovskite surface, which leads to the formation of energy gradients and suppressed trap formation within the perovskite film, as well as a 150 meV improvement of the energetic alignment at the perovskite/SnO2 interface. The combined benefits translate into significant enhancement of the power conversion efficiency to 19% for printable solar cells. The devices without encapsulation degrade only by ≈2% after 700 h in air conditions.
The development of the first high‐performance, printable CsPbI3 solar cells via an ambient blade‐coating technique is reported. High‐quality CsPbI3 films are grown via the introduction of a low concentration of the multifunctional molecular additive Zn(C6F5)2. As a result, the additive‐treated perovskite solar cell delivers a power conversion efficiency (PCE) of 19%.
An aqueous and carbon‐free metal‐oxide precursor route is used in combination with a UV irradiation‐assisted low‐temperature conversion method to fabricate low‐voltage ZnO transistors with electron ...mobilities exceeding 10 cm2/Vs at temperatures <180 °C. Because of its low temperature requirements the method allows processing of high‐performance transistors onto temperature sensitive substrates such as plastic.
A new synthetic route, to prepare an alkylated indacenodithieno3,2‐bthiophene‐based nonfullerene acceptor (C8‐ITIC), is reported. Compared to the reported ITIC with phenylalkyl side chains, the new ...acceptor C8‐ITIC exhibits a reduction in the optical band gap, higher absorptivity, and an increased propensity to crystallize. Accordingly, blends with the donor polymer PBDB‐T exhibit a power conversion efficiency (PCE) up to 12.4%. Further improvements in efficiency are found upon backbone fluorination of the donor polymer to afford the novel material PFBDB‐T. The resulting blend with C8‐ITIC shows an impressive PCE up to 13.2% as a result of the higher open‐circuit voltage. Electroluminescence studies demonstrate that backbone fluorination reduces the energy loss of the blends, with PFBDB‐T/C8‐ITIC‐based cells exhibiting a small energy loss of 0.6 eV combined with a high JSC of 19.6 mA cm−2.
The synthesis of a novel alkylated indacenodithioeno3,2‐bthiophene (C8‐IDTT) based nonfullerene acceptor (C8‐ITIC), is reported. Compared to ITIC with phenylalkyl side chains, the acceptor exhibits a redshifted absorption with increased absorptivity. Solar cell power conversion efficiencies (PCEs) of up to 13.2 % are achieved, with the high PCE attributed to the broad absorption, high crystallinity of C8‐ITIC and low voltage loss.
The charge‐transport processes in organic p‐channel transistors based on the small‐molecule 2,8‐difluoro‐5,11‐bis(triethylsilylethynyl)anthradithiophene (diF‐TES ADT), the polymer ...poly(triarylamine)(PTAA) and blends thereof are investigated. In the case of blend films, lateral conductive atomic force microscopy in combination with energy filtered transmission electron microscopy are used to study the evolution of charge transport as a function of blends composition, allowing direct correlation of the film's elemental composition and morphology with hole transport. Low‐temperature transport measurements reveal that optimized blend devices exhibit lower temperature dependence of hole mobility than pristine PTAA devices while also providing a narrower bandgap trap distribution than pristine diF‐TES ADT devices. These combined effects increase the mean hole mobility in optimized blends to 2.4 cm2/Vs – double the value measured for best diF‐TES ADT‐only devices. The bandgap trap distribution in transistors based on different diF‐TES ADT:PTAA blend ratios are compared and the act of blending these semiconductors is seen to reduce the trap distribution width yet increase the average trap energy compared to pristine diF‐TES ADT‐based devices. Our measurements suggest that an average trap energy of <75 meV and a trap distribution of <100 meV is needed to achieve optimum hole mobility in transistors based on diF‐TES ADT:PTAA blends.
A bandgap state explanation for the performance of organic thin film transistors based on a blend of small molecule and polymer semiconductors is introduced. Organic blend transistors with a range of compositions and mobilities up to 3 cm2/Vs are investigated by means of conductive atomic force microscopy and low temperature electrical measurements, highlighting the requirements for high performance transistors.
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