2023 New's Items

Large-scale efficient mid-wave infrared optoelectronics based on black phosphorus ink

Gupta N
Javey A
2023

The mid-wave infrared (MWIR), ranging from 2 to 5 micrometers, is of substantial interest for chemical sensing, imaging, and spectroscopy. Black phosphorus (bP)–based MWIR light emitters and detectors have been shown to outperform the state-of-the-art for commercial devices due to the low Auger recombination coefficient of bP. However, the scalability of these devices remains a challenge. Here, we report a bP ink formula that preserves the exceptional MWIR optoelectronic properties of bP to deposit centimeter-scale, uniform, and pinhole free films with a photoluminescence quantum...

A composite electrodynamic mechanism to reconcile spatiotemporally resolved exciton transport in quantum dot superlattices

Yuan R
Ginsberg NS
2023

Quantum dot (QD) solids are promising optoelectronic materials; further advancing their device functionality requires understanding their energy transport mechanisms. The commonly invoked near-field Förster resonance energy transfer (FRET) theory often underestimates the exciton hopping rate in QD solids, yet no consensus exists on the underlying cause. In response, we use time-resolved ultrafast stimulated emission depletion (STED) microscopy, an ultrafast transformation of STED to spatiotemporally resolve exciton diffusion in tellurium-doped cadmium selenide–core/cadmium sulfide–...

Detecting, distinguishing, and spatiotemporally tracking photogenerated charge and heat at the nanoscale

Weaver HL
Ginsberg NS
2023

Since dissipative processes are ubiquitous in semiconductors, characterizing how electronic and thermal energy transduce and transport at the nanoscale is vital for understanding and leveraging their fundamental properties. For example, in low-dimensional transition metal dichalcogenides (TMDCs), excess heat generation upon photoexcitation is difficult to avoid since even with modest injected exciton densities, exciton-exciton annihilation still occurs. Both heat and photoexcited electronic species imprint transient changes in the optical response of a semiconductor, yet the unique...

Protein-Based Model for Energy Transfer between Photosynthetic Light-Harvesting Complexes Is Constructed Using a Direct Protein–Protein Conjugation Strategy

Bischoff AJ
Ginsberg NS
Francis MB
2023

Photosynthetic organisms utilize dynamic and complex networks of pigments bound within light-harvesting complexes to transfer solar energy from antenna complexes to reaction centers. Understanding the principles underlying the efficiency of these energy transfer processes, and how they may be incorporated into artificial light-harvesting systems, is facilitated by the construction of easily tunable model systems. We describe a protein-based model to mimic directional energy transfer between light-harvesting complexes using a circular permutant of the tobacco mosaic virus coat protein...

Nonadditive Interactions Unlock Small-Particle Mobility in Binary Colloidal Monolayers

Raybin JG
Wai RB
Ginsberg NS
2023

We examine the organization and dynamics of binary colloidal monolayers composed of micron-scale silica particles interspersed with smaller-diameter silica particles that serve as minority component impurities. These binary monolayers are prepared at the surface of ionic liquid droplets over a range of size ratios (σ = 0.16–0.66) and are studied with low-dose minimally perturbative scanning electron microscopy (SEM). The high resolution of SEM imaging provides direct tracking of all particle coordinates over time, enabling a complete description of the microscopic state. In these...

Operando Label-Free Optical Imaging of Solution-Phase Ion Transport and Electrochemistry

Utterback JK
Ginsberg NS
2023

Ion transport is a fundamental process in many physical, chemical, and biological phenomena, and especially in electrochemical energy conversion and storage. Despite its immense importance, demonstrations of label-free, spatially and temporally resolved ion imaging in the solution phase under operando conditions are not widespread. Here we spatiotemporally map ion concentration gradient evolution in solution and yield ion transport parameters by refining interferometric reflection microscopy, obviating the need for absorptive or fluorescent labels. As an example, we use...

Multimodal Characterization of Crystal Structure and Formation in Rubrene Thin Films Reveals Erasure of Orientational Discontinuities

Tan JA
Dull JT
Rand BP
Ginsberg NS
2023

Multimodal multiscale characterization provide opportunities to study organic semiconducting thin films with multiple length scales, across multiple platforms, to elucidate crystallization mechanisms of the various microstructures that impact functionality. With polarized scanning transmission X-ray and 4D-scanning transmission electron microscopy, hybrid crystalline structures in rubrene thin films in which large crystalline domains surround a common nucleus and transition to a spherulite morphology at larger radii is observed. These high-resolution techniques reveal how azimuthal...

Bidirectional Energy Flow in the Photosystem II Supercomplex

Leonardo C
Yang SJ
Orcutt K
Iwai M
Arsenault EA
Fleming GR
2023

The water splitting capability of Photosystem II (PSII) of plants and green algae requires the system to balance efficient light harvesting along with effective photoprotection against excitation in excess of photosynthetic capacity 1,2, particularly under the naturally fluctuating sunlight intensity. The comparatively flat energy landscape of the...

Chlorophyll to Zeaxanthin Energy Transfer in Non-Photochemical Quenching: An Exciton Annihilation-free Transient Absorption Study

Lee TY
Lam L
Niyogi KK
Fleming GR
2023

Zeaxanthin (Zea) is a key component in the energy-dependent, rapidly reversible, non-photochemical quenching process (qE) that regulates photosynthetic light harvesting. Previous transient absorption (TA) studies suggested that Zea can participate in direct quenching via Chlorophyll (Chl) to Zea energy transfer. However, the contamination of intrinsic exciton-exciton annihilation (EEA) makes the assignment of TA signal ambiguous. In this study, we present EEA-free TA data using Nicotiana benthamiana thylakoid membranes, including wild type and three NPQ mutants...

Kinetics of the xanthophyll cycle and its role in photoprotective memory and response

Short AH
Fay TP
Limmer DT
Fleming GR
2023
Efficiently balancing photochemistry and photoprotection is crucial for survival and productivity of photosynthetic organisms in the rapidly fluctuating light levels found in natural environments. The ability to respond quickly to sudden changes in light level is clearly advantageous. In the alga Nannochloropsis oceanica we observed an ability to respond rapidly to sudden increases in light level which occur soon after a previous high-light exposure. This ability implies a kind of memory. In this work, we explore the xanthophyll cycle in N. oceanica as a short-term photoprotective memory...