A5037199063- solar cell performance optimization
- Nanowire Synthesis and Applications
- Chalcogenide Semiconductor Thin Films
- Machine Learning in Materials Science
- Semiconductor Quantum Structures and Devices
- Silicon and Solar Cell Technologies
- Semiconductor materials and interfaces
- Electronic and Structural Properties of Oxides
- Semiconductor materials and devices
- Metal and Thin Film Mechanics
- GaN-based semiconductor devices and materials
- Quantum Dots Synthesis And Properties
- ZnO doping and properties
- MXene and MAX Phase Materials
- Thin-Film Transistor Technologies
- Inorganic Chemistry and Materials
- Advanced Photocatalysis Techniques
- Advancements in Semiconductor Devices and Circuit Design
- Photonic and Optical Devices
- Optical Coatings and Gratings
- Perovskite Materials and Applications
- Boron and Carbon Nanomaterials Research
- Diamond and Carbon-based Materials Research
- 2D Materials and Applications
- Photonic Crystals and Applications
National Renewable Energy Laboratory
2015-2024
Colorado School of Mines
2015-2024
Computational Physics (United States)
2024
University of Cambridge
2023
Institut für Solarenergieforschung
2019-2021
ORCID
2020-2021
Yale University
2018
Hong Kong University of Science and Technology
2017
California Institute of Technology
2010-2012
University of California, Santa Barbara
2005-2009
Abstract Over the past decade, global cumulative installed photovoltaic (PV) capacity has grown exponentially, reaching 591 GW in 2019. Rapid progress was driven large part by improvements solar cell and module efficiencies, reduction manufacturing costs realization of levelized electricity that are now generally less than other energy sources approaching similar with storage included. Given this success, it is a particularly fitting time to assess state photovoltaics field technology...
Combining two or more junctions into a tandem solar cell promises to deliver leap in power conversion efficiency that will help sustain continued growth installed photovoltaic (PV) capacity. Although tandems are now on the roadmaps of many PV manufacturers, much work remains before they ready for mass deployment. Accelerating their development requires advances fronts. In this article, we outline fundamentals and status PV, considering multiple technology pairings architectures. We then...
II–IV–V<sub>2</sub>materials offer the promise of enhanced functionality in optoelectronic devices due to their rich ternary chemistry.
As the world's demand for energy grows, search cost competitive and earth abundant thin film photovoltaic absorbers is becoming increasingly important. A promising approach to tackle this challenge through photovoltaics made of elements that are in Earth's crust. In work, we focus on Cu2SnS3, a absorber material. Recent publications have presented 3% 6% device efficiencies using Cu2SnS3-based materials alloys, respectively. However, little understood about fundamental defect doping physics...
ZnSnN2 is an Earth-abundant analog to the III-Nitrides with potential as a solar absorber due its direct bandgap, steep absorption onset, and disorder-driven bandgap tunability. Despite these desirable properties, discrepancies in fundamental degenerate \emph{n}-type carrier density have been prevalent issues limited amount of literature available on this material. Using combinatorial RF co-sputtering approach, we able explore growth-temperature-composition space for Zn(1+x)Sn(1-x)N(2) over...
Inorganic nitrides with wurtzite crystal structures are well-known semiconductors used in optical and electronic devices. In contrast, rocksalt-structured known for their superconducting refractory properties. Breaking this dichotomy, here we report ternary nitride rocksalt structures, remarkable properties, the general chemical formula Mg
Interest in inorganic ternary nitride materials has grown rapidly over the past few decades, as their diverse chemistries and structures make them appealing for a variety of applications. Due to synthetic challenges posed by stability N 2 , number predicted compounds dwarfs that been synthesized, offering breadth opportunity exploration. This review summarizes fundamental properties structural chemistry nitrides, leveraging metastability impact nitrogen chemical potential. A discussion...
We have developed a wet chemical digital etching technique for tuning the resonant wavelengths of photonic crystal (PC) nanocavities over wide range 80nm in precise 2–3nm steps while preserving high cavity quality factors. In one step, few monolayers material are removed from surface by self-formed native oxide 1mol citric acid. Due to self-limiting thickness, total is based only on number etch steps, resulting highly controlled, ability. characterized behavior GaAs PC defect cavities both...
In multinary compound semiconductors, cation disorder can decisively alter the electronic properties and impact potential applications. $\mathrm{ZnSn}{\mathrm{N}}_{2}$ is a ternary nitride of interest for photovoltaics, which forms in wurtzite-derived crystal structure. ground state, every N anion coordinated by two Zn Sn cations, thereby observing octet rule locally. Using motif-based model Hamiltonian, we performed Monte Carlo simulations that provide atomistic representations with varying...
Three-terminal tandem solar cells can provide a robust operating mechanism to efficiently capture the spectrum without need current match sub-cells or fabricate complicated metal interconnects.
Tandem and multijunction solar cells offer the only demonstrated path to terrestrial 1-sun cell efficiency over 30%. Three-terminal tandem (3TT) can overcome some of limitations two-terminal four-terminal designs. However, coupled nature adds a degree complexity devices themselves ways that their performance be measured reported. While many different configurations 3TT have been proposed, there is no standard taxonomy discuss device structure or loading topology. This Perspective proposes...
Enhanced acceptor activation is achieved in the ternary nitride semiconductor ZnSnN2. Hydrogen passivation of acceptors during growth, coupled with post-growth annealing to remove hydrogen, suppresses native donor formation and moves Fermi energy away from conduction band minimum. This technique produces nondegenerate zinc tin 1016 cm−3 electron concentration.
Controlling site disorder in ternary and multinary compounds enables tuning optical electronic properties at fixed lattice constants stoichiometries, moving beyond many of the challenges facing binary alloy systems. Here, we consider possible enhancements to energy-related applications through integration disorder-tunable materials devices such as light-emitting diodes, photonics, photovoltaics, photocatalytic materials, batteries, thermoelectrics. However, remain controlling characterizing...
Nitride materials feature strong chemical bonding character that leads to unique crystal structures, but many ternary nitride spaces remain experimentally unexplored. The search for previously undiscovered nitrides is also an opportunity explore properties, such as transitions between cation-ordered and -disordered well identify candidate optoelectronic applications. Here, we present a comprehensive experimental study of MgSnN2, emerging II–IV–N2 compound, the first time mapping phase...
Although Si dominates the photovoltaics market, only two forms of have been thoroughly considered: amorphous and in diamond structure ( d-Si). Silicon can also form other allotropes, including clathrate structures. clathrates are inclusion compounds, which consist an framework surrounding templating guest atoms (e.g., Na). After formation type II Na <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">24</sub>...
Inorganic type II clathrates are low density, semiconducting allotropes of group IV elements with the potential for optoelectronic applications. This class materials is predicted to have direct or nearly-direct band gaps, and, when Si and Ge alloyed in clathrate structure, gap tunable range 0.8–1.8 eV. In this work, we demonstrate first time synthesis Si–Ge clathrates. Within alloy system, find an amorphous region which likely due a miscibility gap. The optical absorptance spectra...
ZnSiP<sub>2</sub>is a promising candidate for lattice-matched tandem photovoltaics on silicon. Here, we explore the defect physics, luminescence, and photoelectrochemical performance of this potential top cell material.
Three-terminal tandem solar cell with conductive adhesive interconnect and back-contacted bottom delivers 27.3% efficiency.
Exciton photoluminescence is observed in disordered zinc tin nitride as a result of benign defect complex formation encouraged by annealing.
Zn<sub>2</sub>SbN<sub>3</sub> is the first Sb-based crystalline nitride and a photoactive semiconductor.
Photoelectrochemical fuel generation is a promising route to sustainable liquid fuels produced from water and captured carbon dioxide with sunlight as the energy input. Development of these technologies requires photoelectrode materials that are both photocatalytically active operationally stable in harsh oxidative and/or reductive electrochemical environments. Such photocatalysts can be discovered based on co-design principles, wherein design for stability propensity photocatalyst...