Hybrid Perovskite Materials Research Articles

Effect of nano-nucleation sites assisted crystallization on performance of perovskite photodetector

<sec>Photodetector occupies an important position in the sensor family, but most of the photoelectric conversion materials of photodetectors are inorganic semiconductors, such as GaAs, GaN, Ge and Si, these inorganic semiconductors are usually prepared by complicated methods and high cost, and furthermore, they have poor mechanical flexibility. Organic-inorganic hybrid perovskite materials serving as visible-light sensitizers have the advantages of balanced electron and hole mobilities, adjustable bandgaps, high absorption coefficients, low temperature solution preparation, which make the materials a suitable candidate for inorganic semiconductors.</sec><sec>For planar photodetectors, carriers have greater probabilities to be trapped by the defects in the perovskite films, therefore it is important to fabricate a high-quality perovskite film. However, owing to the low formation energy of perovskite crystals, defects prove to occur on the film surface and grain boundaries, which aggravate the performance of perovskite optoelectronic devices. In this work, we introduce a small quantity of graphene oxide nanosheets (GOSs) on bare glass substrate as effective nucleation sites of perovskite crystals. Owing to the extremely low density of GOSs and large exposed glass basement, the GOSs cannot be regarded as an interface layer. The existence of GOSs on smooth substance reduces the perovskite nucleation barrier, leading to a more preferential crystal growth in these locations, and binds tightly with glass substrate, which passivates the defects efficiently. Meanwhile, the element of O in the GOSs can create Pb–O bond with Pb in the CH<sub>3</sub>NH<sub>3</sub>PbI<sub>3</sub>, further improving the crystal of perovskite. On this basis, planner perovskite photodetector with a structure of glass/GOSs/CH<sub>3</sub>NH<sub>3</sub>PbI<sub>3</sub>/MoO<sub>3</sub>/Au is fabricated. By adjusting the concentration of GOSs deionized water dispersion under the same spin-coating condition, the photoelectric conversion performance of perovskite photodetector is enhanced. Under the influence of the optimal concentration of GOSs, photocurrent of the champion photodetector (1.15 × 10<sup>–6</sup> A) is an order of magnitude higher than that of reference device without GOSs modified (3.58 × 10<sup>–7</sup> A) at 3 V bias, leading to a high ON/OFF current ratio of 5.22 × 10<sup>3</sup>. Besides, improved photoresponse speed is also found in the champion device, with a rise time of 9.6 ms and a decay time of 6.6 ms, respectively. The enhanced performance of GOSs modified perovskite photodetector can be attributed to the significantly reduced defects bringing about an enhanced charge separation and collection performance in the CH<sub>3</sub>NH<sub>3</sub>PbI<sub>3</sub> films.</sec><sec>By introducing extremely low quantity GOSs as the effective perovskite crystal nucleation sites, the perovskite crystallization and thin film can be effectively improved, leading to a positive effect on the performance of perovskite photodetector. This method has a certain universality, and therefore it has a reference value for other structures of perovskite photoelectric devices.</sec>

Preparation of highly efficient and stable CsPbBr3 perovskite solar cells based on an anti-solvent rinsing strategy

CsPbBr 3 perovskite solar cell has become a hot research object due to its excellent stability. It has been proved that anti-solvent washing is a good way to improve the crystal quality of organic-inorganic hybrid perovskite materials using a one-step spin-coating method. However, it is rarely reported in the preparation of all-inorganic perovskite materials. Here, an anti-solvent rinsing strategy was introduced for the synthesis of CsPbBr 3 films via the multi-step spin-coating process. We found that the addition of anti-solvent with high boiling points could significantly improve the surface morphology and crystal quality of CsPbBr 3 films by optimizing the nucleation and crystallization of PbBr 2 films. By virtue of the anti-solvent rinsing strategy, the highest efficiency of 9.6% and long-term stability over 800 h in ambient air without encapsulation were achieved. Our conclusions provide a certain reference value for the preparation of highly efficient and stable CsPbBr 3 perovskite solar cells. ● An anti-solvent rinsing strategy was introduced for the synthesis of CsPbBr 3 films via the multi-step spin-coating process. ● We found that the addition of anti-solvents with high boiling points could significantly improve the surface morphology and crystal quality of CsPbBr 3 films by optimizing the nucleation and crystallization of PbBr 2 films. ● By virtue of the anti-solvent rinsing strategy, a highest power conversion efficiency of 9.6% and long-term stability over 800 h in ambient air without encapsulation were achieved.

Decreasing toxicity and increasing photoconversion efficiency by Sn-substitution of Pb in 5-ammonium valeric acid-based two-dimensional hybrid perovskite materials.

The toxicity of Pb in halide-based hybrid perovskite materials stands in the way of their more extensive use, despite their excellent optical properties, high stability and very good photoconversion efficiency. The presented work focuses on addressing the toxicity issues in 2D perovskites. We use 5-ammonium valeric acid (AVA) as an organic spacer and partially or completely eliminate Pb by Sn and apply first principles-based density functional theory (DFT) calculations to determine the properties of these systems. Structural insights are gained, which predict the major changes in the inorganic framework including the metal-halide bond length and the bridging angle between two octahedral configurations. The replacement of Pb by Sn leads to a drastic reduction of the electronic band gap from 1.84 to 1.04 eV. Increasing the Sn content results in Sn-I bonds being stronger than the Pb-I bonds, which entails strong s-p coupling. The calculated effective masses of excitons decrease by up to ∼23% in the case of lead-free perovskites, which can be attributed to the more dispersive band edges due to stronger s-p coupling. The reduction of the effective masses of the charge carriers and the electronic band gap results in high electrical conductivity for the AVA2(MA)Sn2I7 2D perovskite structure. The three structures compared, where AVA2(MA)XI7 (X = Pb2, PbSn, Sn2) exhibit excellent thermoelectric power factors, which suggests promising applications for heat energy conversion. Moving toward lead-free 2D perovskites, the real part of the dielectric constants enhances, which may limit the radiative recombination of charge carriers. Furthermore, reducing the bandgap values by the substitution of Sn results in a red-shift in the edge of the absorption coefficients. Using the spectroscopic limited maximum efficiency (SLME) model, the best efficiencies of 32.20 and 30.08% are achieved for the AVA2(MA)PbSnI7 and AVA2(MA)Sn2I7 structures. The comparison of all three structures demonstrates that lead-free 2D perovskites are very good candidates for highly efficient solar energy conversion.

A lead bromide organic-inorganic hybrid perovskite material showing reversible dual phase transition and robust SHG switching.

A one-dimensional organic-inorganic hybrid perovskite material [3.3.0-dabco]PbBr3 (1) was synthesized by the reaction of 1,5-diazabicyclo[3.3.0]octane (3.3.0-dabco) with PbBr2 in concentrated HBr aqueous solution. Differential scanning calorimetry, dielectric measurements, and variable-temperature structural analyses revealed that compound 1 exhibits two successive structural phase transitions from P212121 to Pbcm at 387 K (T1) and then to P6/mmc at 436 K (T2), accompanied by two pairs of dielectric anomalies with a clear one at T1 and an unobvious one at T2. In addition, compound 1 shows a robust second harmonic generation (SHG) effect between SHG-OFF and SHG-ON states during its centrosymmetric to non-centrosymmetric symmetry breaking phase transition at T1.

Spatial microheterogeneity in the valence band of mixed halide hybrid perovskite materials.

The valence band of lead halide hybrid perovskites with a mixed I/Br composition is investigated using electronic structure calculations and complementarily probed with hard X-ray photoelectron spectroscopy. In the latter, we used high photon energies giving element sensitivity to the heavy lead and halide ions and we observe distinct trends in the valence band as a function of the I : Br ratio. Through electronic structure calculations, we show that the spectral trends with overall composition can be understood in terms of variations in the local environment of neighboring halide ions. From the computational model supported by the experimental evidence, a picture of the microheterogeneity in the valence band maximum emerges. The microheterogeneity in the valence band suggests that additional charge transport mechanisms might be active in lead mixed halide hybrid perovskites, which could be described in terms of percolation pathways.

Defects and passivation in perovskite solar cells

This organic-inorganic hybrid perovskite materials have attracted great attention by virtue of their high absorption coefficient, low cost and simple film deposition technique. Based on these advantages, perovskite solar cells have reached an impressive power conversion efficiency over 25%. However, the low-temperature process inevitably leads to a large number of defects in the perovskite film. These defects would exacerbate the carrier recombination, induce crystal degradation, phase transformation and seriously affect the performance of devices. Studying the defects in perovskite film is of great significance for the development of high-performance perovskite solar cells. Herein, the authors summarise the causes, distribution and features of defects, as well as their effects on the performance of perovskite solar cells. Furthermore, some defect-passivation strategies on perovskite film or the device, including grain boundary passivation, surface passivation, capping layer modification and charge transport layer passivation, are discussed, respectively. Lastly, some remaining challenges in the commercialisation of perovskite solar cells are proposed.

β-Diketone Coordination Strategy for Highly Efficient and Stable Pb-Sn Mixed Perovskite Solar Cells.

The narrow bandgap Pb-Sn hybrid perovskite materials with lower toxicities and adjustable optical bandgaps provide the opportunity to construct high-efficiency perovskite solar cells (PerSCs). To solve the issues of the uncontrollable crystallization rate of Pb-Sn perovskite and easy oxidation of Sn2+, a β-diketone-based additive, N,N,N',N'-tetraphenylmalondiamide (TPMA), is introduced to coordinate with Pb2+ and Sn2+. The introduction of TPMA can improve the morphology of perovskite films and decrease the density of defect states, resulting in an enhanced power conversion efficiency of >20% and improved stability. The PerSC without encapsulation retains 94% of its initial efficiency after being stored for 1000 h in a nitrogen-filled glovebox and shows a lifetime of only 8% degradation after being continuously heated for 100 h at 80 °C. This work represents a new strategy of introducing a β-diketone ligand as an additive in precursor engineering for achieving efficient and stable PerSCs.

Design of (C3N2H5)(1-)Cs PbI3 as a novel hybrid perovskite with strong stability and excellent photoelectric performance: A theoretical prediction

Due to its unique properties, such as long carrier diffusion length and adjustable optical band gap, organic-inorganic hybrid perovskite has been a potentially strong photoelectric material for solar cells. However, the challenge of insufficient stability of perovskite materials has not been solved, which in turn, limits its commercial application. Inspired by the strong stability of C3N2H5PbI3 (ImPbI3), we present an innovative doped system, Im(1-x)CsxPbI3 (x = 0.25, 0.5, 0.75), based on the cation-doped strategy, to obtain both strong stability and excellent photoelectric performance. A new perovskite phase ImPbI3 is proposed and verified rationality of existence through formation energy, ab initio molecular dynamics (AIMD), mean square displacement (MSD), and X-ray diffraction (XRD) based on density functional theory (DFT) calculations. For analyzing the photoelectric properties of Im(1-x)CsxPbI3, the bandgap, charge distribution of the frontier molecular orbital, and projected density of states are investigated. To study the stability of Im(1-x)CsxPbI3, geometric configuration, tolerance factor, crystal orbital Hamilton populations (COHP), and AIMD simulations are performed. The results show that the perovskite phase ImPbI3 has strong thermodynamic stability and structural stability, and its optical bandgap value is lower than that of the hexagonal system. When the content of doped Cs does not exceed 50%, the stability of the perovskite phase ImPbI3 is significantly improved. Comprehensive analysis shows that Im0.5Cs0.5PbI3 exhibits encouraging performance with strong stability and high optical absorption coefficient. This theoretical study opens a new avenue for the design of robust organic-inorganic hybrid perovskite materials with strong stability and excellent photoelectric performance based on our findings from perovskite phase ImPbI3 system.

Inkjet printed organic light-emitting diodes employing organometal-halide perovskite as hole transport layer

Due to their narrow spectrum and high photoluminescence quantum yield, organic-inorganic hybrid perovskite materials have become an important emitter for light-emitting diodes (LED). In addition to the perovskite emitters, other perovskite materials such as methyl lead ammonium chloride (MAPbCl3) with high charge mobility can potentially be used as excellent charge transport materials. In this work, phosphorescence LED devices in which MAPbCl3 was employed as hole transport layer (HTL) was designed and fabricated by inkjet printing (IJP) process. Ethanolamine was added to the poly(3,4-ethylenedioxythiophene):poly-(styrenesulfonate) hole injection layer (HIL) to control the crystallization process and to suppress the surface defects of MAPbCl3. In addition, polyethylene oxide was doped into MAPbCl3 to improve the printability and the quality of film formation. The ‘blurred interface’ concept was successively applied to enable for the first time the IJP of three layers (HIL, HTL and emitter layers) in the LEDs. The fabricated multilayer LEDs achieved the maximum external quantum efficiency of 8.9%, maximum current efficiency of 30.8 cd A−1, and maximum power efficiency of 10.7 lm W−1. A 40 × 40 mm2 OLED light emitting device was successfully fabricated by IJP technology.

Unusual terahertz-wave absorptions in \u03b4/\u03b1-mixed-phase FAPbI3 single crystals: interfacial phonon vibration modes

The terahertz (THz)-wave absorption properties in organic-inorganic hybrid perovskite (OHP) materials are investigated with the in-depth development of OHP-based THz applications. In the THz range from 0.5 to 3 THz, OHPs typically show several interesting phonon modes such as transverse, longitudinal, and halogen self-vibrations. To modulate these frequencies, the density changes in defect-incorporated structures and element mixtures were tested and confirmed. In the literature, the origin of phonon modes in OHP materials have been mostly explained. However, we found new phonon vibration modes in formamidinium (FA)-based hybrid perovskite structures. FAPbI3 single crystals, organic–inorganic hybrid perovskites, of the δ-, δ/α-mixed-, and α-phases were prepared. We intriguingly found that the δ/α-mixed-phase exhibited significant THz-wave absorption peaks at 2.0 and 2.2 THz that were not related to any phonon modes from either the δ- or α-phases, although the δ/α-mixed-phase sample was confirmed to be formed by a physical combination of the δ- and α-phases without the creation of any new chemical states. Our theoretical study performed with ab initio calculations provides an explanation for these unusual THz-wave absorption behaviors; they originate from the novel vibration modes excited at the seamless interfaces in the mixed phase of FAPbI3.

Degradation mechanism of CH3NH3PbI3 and enhancing its optical absorption through variety of doping sites

Hybrid perovskite materials have attracted a lot of attention, owing to their remarkable properties in different application fields. Yet, they represent some drawbacks, such as their high degradation which influences its performances. In this work, based on the density functional theory, we study the doping of the CH3NH3PbI3 by bromine (Br), we reveal that Br’ site improves the electrical conductivity of CH3NH3PbI3, and shows a higher absorption coefficient which covers almost the entire visible spectrum. The doping in Br’ site also improves the stability of the CH3NH3PbI3 structure by the presence of small imaginary acoustic phonon modes. In order to study the degradation mechanism of CH3NH3PbI3, oxygen (O) inter-site was used. Results demonstrated that oxygen (O) inter-site in the CH3NH3PbI3 system tends to make a strong interaction with iodine (I), lead (Pb), and hydrogen (H) which causes the displacement of inorganic element towards the organic plan. In the case of the doping by bromine (Br), the system showed less displacement of elements, and the O–Br bond is found to be unfavorable.

Fundamental Physical Properties of Nontoxic Tin‐Based Formamidinium FASnX3 (X = I, Br, Cl) Hybrid Halide Perovskites: Future Opportunities in Photovoltaic Applications

To analyze potential alternatives, the fundamental physical properties such as structural, electronic, optical, elastic, thermoelectric, and thermodynamic parameters of tin‐based formamidinium FASnX3 (X = I, Br, Cl) hybrid halide perovskites by using density functional theory are investigated. The calculated results indicate that these compounds exhibit analogous band gap, considerable thermal and elastic stability, and notable optical properties with high dielectric constant and absorption coefficient, significant hole, and electron conductive behavior. The present research work shows as good absorbers for perovskite solar cells, adding to the validity of FP‐LAPW (full‐potential linearized augmented plane wave) methods, simultaneously enhancing the understanding of these practical hybrid perovskite materials. It may be believed that this study will be of a lot of credit for experimentalists for synthesis and characterization of these materials and will be done experimentally in future times due to the very good properties of photovoltaic applications.

On the Shape-Selected, Ligand-Free Preparation of Hybrid Perovskite (CH3NH3PbBr3) Microcrystals and Their Suitability as Model-System for Single-Crystal Studies of Optoelectronic Properties

Hybrid perovskite materials are one of the most promising candidates for optoelectronic applications, e.g., solar cells and LEDs, which can be produced at low cost compared to established materials. Although this field of research has seen a huge upsurge in the past decade, there is a major lack in understanding the underlying processes, such as shape-property relationships and the role of defects. Our aerosol-assisted synthesis pathway offers the possibility to obtain methylammonium lead bromide (MAPbBr3) microcrystals from a liquid single source precursor. The differently shaped particles are aligned on several substrates, without using a directing agent or other additives. The obtained particles show good stability under dry conditions. This allows us to characterize these materials and their pure surfaces at the single-crystal level using time- and spatially resolved methods, without any influences of size-dependent effects. By optimizing the precursor for the aerosol process, we were able to eliminate any purification steps and use the materials as processed. In addition, we performed theoretical simulations to deepen the understanding of the underlying processes in the formation of the different crystal facets and their specific properties. The model system presented provides insights into the shape-related properties of MAPbBr3 single crystals and their directed but ligand-free synthesis.

Self-powered perovskite CH3NH3PbBr3 field effect transistor with fast response and high sensitivity in sensing

Organic-inorganic hybrid perovskite materials possess advantages over other candidate classes for chemo-sensory materials because of their structural tunability and stability. In this work, we prepared highly qualitied MAPbBr3 perovskite crystals to provide a high carrier mobility to enhance the sensing on gas, where the response time of sensing below 0.1 s is obtained. Because the perovskite field effect transistor provides a large surface to adsorb gas, the sensitivity of detection can reach 0.2 ppm. Furthermore, combining with theoretical simulation, we analyzed the binding energy, electronic structure, and charge transfer density between perovskite surface (including PbBr2-terminated surface and CH3NH3Br-terminated surface) and gas molecules to study the mechanism behind the phenomena. It is obtained that enhancing the interfacial charge transfer density and then suppressing the recombination of transferred charges will effectively increase the sensitivity of the sensor.

Evolution of hybrid organic–inorganic perovskite materials under external pressure

Hybrid organic–inorganic perovskites (HOIPs) are the emerging family of perovskite materials showing a diverse plethora of unique optoelectronic properties for promising energy applications for sustainable and green environment. These materials also show potential promise for fine tuning of structural, electronic, and optical properties under external stimuli like pressure, temperature, and electric field, which are having pertinent applications in the form of energy materials. This review portrays a critical take on the recent progress of pressure-induced structural, electronic, and optical properties tuning in hybrid perovskite materials under the influence of external pressure both from theoretical and experimental viewpoints. It also shows insight on the relevant and timely issues like encountering inaccessible structural phases through lattice distortion along with the Jahn–Teller distortions, evolution of bandgap and photoluminescence, Rashba-splitting, charge carrier mobility, and piezochromism under external hydrostatic pressure. Finally, explicit options on the future research scope including the enhanced properties in barocaloric materials under compression have been portrayed for HOIP materials family.

The Future of Hybrid and Inorganic Perovskite Materials: Technology Forecasting

Perovskite (PSK) materials have received extensive attention because of their potential use as the active layer of different applications, including capacitors, sensors and detectors, memories, catalysts, fuel cells, and optoelectronic devices (solar cell and light‐emitting diode). Herein, the past, current, and future status of these applications are focused on. The state of each application is investigated using diverse technology indicators. It reveals that among all the applications, the optoelectronic application is the youngest one and has not yet reached the technology growth stage though it possesses most of the recently published patents. Using a technology investment potential evaluation method, the most potent area for investment is explored, indicating that detectors and sensors are the ones with the biggest investment potentials. Remarkably, PSK solar cell dedicates more than 70% of the patents to itself with the highest predicted efficiency of 30% that will be achieved in 2023 according to the curve fitting method and in 2030 according to the S‐curve method. As a perspective, currently, the highest efficiency and stability are achieved for small‐sized PSK solar cells, it is expected that they would be commercialized in electronic equipment applications first, and after overcoming the challenges, large‐scale modules would enter the markets.

Pyrene‐Based Small‐Molecular Hole Transport Layers for Efficient and Stable Narrow‐Bandgap Perovskite Solar Cells

Lead–tin (Pb–Sn) hybrid perovskite materials possess ideal narrow bandgaps (1.2–1.4 eV) for efficient single‐junction and tandem solar cells. Poly(3,4‐ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) is commonly used as hole transport layer (HTL) for Pb–Sn perovskite solar cells (PSCs), despite its poor stability with these perovskites. Here, two new octacyclic heteroaromatic molecules, pyrenodiindole (PDI) and pyrenodi‐(7‐azaindole) (PDAI), are presented as the HTL for narrow‐bandgap (1.23 eV) p–i–n Pb‐Sn PSCs. The self‐assembled reciprocal hydrogen‐bonded solid‐state structure of PDAI bestows robustness compared to PDI, making it less vulnerable in processing the perovskite film on top, and improves the reproducibility of device fabrication. Transient photocurrent measurements and light‐intensity‐dependent device characteristics indicate that PDI and PDAI possess similar hole extraction properties to PEDOT:PSS. As a result, similar open‐circuit voltages and fill factors are obtained in the PSCs. Interestingly, the use of thin PDI and PDAI as HTL in PSCs changes the optical interference and reduces parasitic absorption in the near‐infrared region, resulting in an improved short‐circuit current density. Consequently, a higher power conversion efficiency of 16.1% is obtained for PDI and PDAI, compared to 15.1% for PEDOT:PSS. In addition, the self‐assembled structure of PDAI led to a notable enhancement of device stability.

Naphthalenediimide/Formamidinium-Based Low-Dimensional Perovskites

Low-dimensional hybrid perovskites have emerged as promising materials for optoelectronic applications. Although these materials have already demonstrated enhanced stability as compared to their three-dimensional perovskite analogues, their functionality has been limited by the insulating character of the organic moieties that primarily play a structure-directing role. This is particularly the case for the layered (2D) perovskite materials based on formamidinium lead iodide (FAPbI3) that remain scarce. We demonstrate a low-dimensional hybrid perovskite material based on a SPbI4 composition incorporating an electroactive naphthalenediimide (NDI) moiety as an organic spacer (S) between the perovskite slabs and evidence the propensity of the spacer to stabilize the α-FAPbI3 perovskite phase in hybrid low-dimensional SFAn–1PbnI3n+1 perovskite compositions. This has been investigated by means of solid-state nuclear magnetic resonance spectroscopy in conjunction with molecular dynamics simulations and density functional theory calculations. Theoretical calculations suggest an electronic contribution of the organic spacer to the resulting optoelectronic properties, which was confirmed by transient absorption spectroscopy. We have further analyzed these materials by time-resolved microwave conductivity measurements, revealing challenges for their application in photovoltaics.

The Contribution of NMR Spectroscopy in Understanding Perovskite Stabilization Phenomena.

Although it has been exploited since the late 1900s to study hybrid perovskite materials, nuclear magnetic resonance (NMR) spectroscopy has only recently received extraordinary research attention in this field. This very powerful technique allows the study of the physico-chemical and structural properties of molecules by observing the quantum mechanical magnetic properties of an atomic nucleus, in solution as well as in solid state. Its versatility makes it a promising technique either for the atomic and molecular characterization of perovskite precursors in colloidal solution or for the study of the geometry and phase transitions of the obtained perovskite crystals, commonly used as a reference material compared with thin films prepared for applications in optoelectronic devices. This review will explore beyond the current focus on the stability of perovskites (3D in bulk and nanocrystals) investigated via NMR spectroscopy, in order to highlight the chemical flexibility of perovskites and the role of interactions for thermodynamic and moisture stabilization. The exceptional potential of the vast NMR tool set in perovskite structural characterization will be discussed, aimed at choosing the most stable material for optoelectronic applications. The concept of a double-sided characterization in solution and in solid state, in which the organic and inorganic structural components provide unique interactions with each other and with the external components (solvents, additives, etc.), for material solutions processed in thin films, denotes a significant contemporary target.

Cryogenic Electron Microscopy for Energy Materials.

The development of clean energy generation, transmission, and distribution technology, for example, high energy density batteries and high efficiency solar cells, is critical to the progress toward a sustainable future. Such advancement in both scientific understanding and technological innovations entail an atomic- and molecular-resolution understanding of the key materials and fundamental processes governing the operation and failure of the systems. These dynamic processes span multiple length and time scales bridging materials and interfaces involved across the entire device architecture. However, these key components are often highly sensitive to air, moisture, and electron-beam radiation and therefore remain resistant to conventional nanoscale interrogation by electron-optical methods, such as high-resolution (scanning) transmission electron microscopy and spectroscopy.Fortunately, the rapid progress in cryogenic electron microscopy (cryo-EM) for physical sciences starts to offer researchers new tools and methods to probe these otherwise inaccessible length scales of components and phenomena in energy science. Specifically, weakly bonded and reactive materials, interfaces and phases that typically degrade under high energy electron-beam irradiation and environmental exposure can potentially be protected and stabilized by cryogenic methods, bringing up thrilling opportunities to address many crucial yet unanswered questions in energy science, which can eventually lead to new scientific discoveries and technological breakthroughs.Thus, in this Account, we aim to highlight the significance of cryo-EM to energy related research and the impactful results that can be potentially spawned from there. Due to the limited space, we will mainly review representative examples of cryo-EM methodology for lithium (Li)-based batteries, hybrid perovskite solar cells, and metal-organic-frameworks, which have shown great promise in revealing atomic resolution of both structural and chemical information on the sensitive yet critical components in these systems. We will first emphasize the application of cryo-EM to resolve the nanostructure and chemistry of solid-electrolyte interphases, cathode-electrolyte interphase, and electrode materials in batteries to reflect how cryo-EM could inspire rational materials design and guide battery research toward practical applications. We then discuss how cryo-EM helped to reveal guest intercalation chemistry in weakly bonded metal-organic-frameworks to develop a complete picture of host-guest interaction. Next, we summarize efforts in hybrid perovskite materials for solar cells where cryo-EM preserved the volatile organic molecules and protected perovskites from any air or moisture contamination. Finally, we conclude with perspectives and brief discussion on future directions for cryo-EM in energy and materials science.