Rasmus Svejstrup Nielsen
@drnielsen.bsky.social
My name is Rasmus, and I'm currently a postdoctoral fellow (funded by the Carlsberg Foundation) in the Nanomaterials Spectroscopy and Imaging group within the Transport at Nanoscale Interfaces Lab at EMPA in Switzerland.
Excited to share our work on quasi-1D chalcohalides — optical gaps from 1.3–2.1 eV and we’ve mapped out their electron-phonon coupling. These materials have some seriously interesting optoelectronic possibilities 🤘
doi.org/10.1039/D5TA...
doi.org/10.1039/D5TA...
October 5, 2025 at 3:58 PM
Excited to share our work on quasi-1D chalcohalides — optical gaps from 1.3–2.1 eV and we’ve mapped out their electron-phonon coupling. These materials have some seriously interesting optoelectronic possibilities 🤘
doi.org/10.1039/D5TA...
doi.org/10.1039/D5TA...
BaZrS₃ lights up!!! 🔥✨☀️
From high-quality single crystals, we show BaZrS₃ is an intrinsically strongly luminescent chalcogenide perovskite. The carrier lifetime is short, the electron–phonon coupling a bit unusual – but it glows bright!
Read it before your neighbour 👉 doi.org/10.1002/adom...
From high-quality single crystals, we show BaZrS₃ is an intrinsically strongly luminescent chalcogenide perovskite. The carrier lifetime is short, the electron–phonon coupling a bit unusual – but it glows bright!
Read it before your neighbour 👉 doi.org/10.1002/adom...
September 18, 2025 at 9:51 AM
BaZrS₃ lights up!!! 🔥✨☀️
From high-quality single crystals, we show BaZrS₃ is an intrinsically strongly luminescent chalcogenide perovskite. The carrier lifetime is short, the electron–phonon coupling a bit unusual – but it glows bright!
Read it before your neighbour 👉 doi.org/10.1002/adom...
From high-quality single crystals, we show BaZrS₃ is an intrinsically strongly luminescent chalcogenide perovskite. The carrier lifetime is short, the electron–phonon coupling a bit unusual – but it glows bright!
Read it before your neighbour 👉 doi.org/10.1002/adom...
Not all defects are killers! 🔬 Our combined theory-experiment study shows an intrinsic point defect tolerance in trigonal selenium, suggesting interface and extended defects to limit performance. Selenium is still in the game for tandem and indoor PV! ☀️⚡ doi.org/10.1039/D4EE...
Intrinsic point defect tolerance in selenium for indoor and tandem photovoltaics
Selenium has reemerged as a promising absorber material for tandem and indoor photovoltaic (PV) devices due to its elemental simplicity, unique structural features, and wide band gap. However, despite...
doi.org
June 9, 2025 at 1:03 PM
Not all defects are killers! 🔬 Our combined theory-experiment study shows an intrinsic point defect tolerance in trigonal selenium, suggesting interface and extended defects to limit performance. Selenium is still in the game for tandem and indoor PV! ☀️⚡ doi.org/10.1039/D4EE...
Reposted by Rasmus Svejstrup Nielsen
Intrinsic & extrinsic (dopant) defect chemistry of trigonal Selenium for PV, incl metastable states & non-radiative recombination ⬇️
Combined theory & expt analysis, we find an intrinsic tolerance to 𝘱𝘰𝘪𝘯𝘵 defects, with GBs/interfaces the limiting factor for PV 📈
pubs.rsc.org/en/Content/A...
Combined theory & expt analysis, we find an intrinsic tolerance to 𝘱𝘰𝘪𝘯𝘵 defects, with GBs/interfaces the limiting factor for PV 📈
pubs.rsc.org/en/Content/A...
Intrinsic point defect tolerance in selenium for indoor and tandem photovoltaics
Selenium has reemerged as a promising absorber material for tandem and indoor photovoltaic (PV) devices due to its elemental simplicity, unique structural features, and wide band gap. However, despite...
pubs.rsc.org
April 15, 2025 at 1:16 PM
Intrinsic & extrinsic (dopant) defect chemistry of trigonal Selenium for PV, incl metastable states & non-radiative recombination ⬇️
Combined theory & expt analysis, we find an intrinsic tolerance to 𝘱𝘰𝘪𝘯𝘵 defects, with GBs/interfaces the limiting factor for PV 📈
pubs.rsc.org/en/Content/A...
Combined theory & expt analysis, we find an intrinsic tolerance to 𝘱𝘰𝘪𝘯𝘵 defects, with GBs/interfaces the limiting factor for PV 📈
pubs.rsc.org/en/Content/A...
#PVMagazine just highlighted our most recent work on characterizing selenium thin film solar cells using the recently developed carrier-resolved photo-Hall technique! Check it out! 😎 🔥
www.pv-magazine.com/2025/04/15/n...
www.pv-magazine.com/2025/04/15/n...
New research sheds light on intrinsic limitations of selenium solar cells
Danish researchers have analyzed fundamental material properties of selenium solar cells and have found their potential is higher than generally believed. They used carrier-resolved photo-Hall analysi...
www.pv-magazine.com
April 15, 2025 at 8:48 AM
#PVMagazine just highlighted our most recent work on characterizing selenium thin film solar cells using the recently developed carrier-resolved photo-Hall technique! Check it out! 😎 🔥
www.pv-magazine.com/2025/04/15/n...
www.pv-magazine.com/2025/04/15/n...
Determining "simple" material properties is not a simple task! Here, we combine carrier-resolved photo-Hall measurements with other advanced characterization techniques and device simulations to resolve reported discrepancies in selenium thin films! 🔬 ☀️ ⚡
doi.org/10.1103/Phys...
doi.org/10.1103/Phys...
Variable-temperature and carrier-resolved photo-Hall measurements of high-performance selenium thin-film solar cells
Selenium is a promising absorber material for the next generation of solar cells, but unlocking its full potential requires a deeper understanding of both the minority and majority charge carriers. Us...
doi.org
April 6, 2025 at 2:40 PM
Determining "simple" material properties is not a simple task! Here, we combine carrier-resolved photo-Hall measurements with other advanced characterization techniques and device simulations to resolve reported discrepancies in selenium thin films! 🔬 ☀️ ⚡
doi.org/10.1103/Phys...
doi.org/10.1103/Phys...
Reposted by Rasmus Svejstrup Nielsen
The latest version of 𝙙𝙤𝙥𝙚𝙙 (and 𝑺𝒉𝒂𝒌𝒆𝑵𝑩𝒓𝒆𝒂𝒌), our defect modelling python packages, have been released!
Incl:
- Major efficiency updates
- Advanced defect/carrier thermodynamics w/custom constraints
- Auto shallow defect handling
- CC diagram generation
...🧵👇
Incl:
- Major efficiency updates
- Advanced defect/carrier thermodynamics w/custom constraints
- Auto shallow defect handling
- CC diagram generation
...🧵👇
February 4, 2025 at 4:28 PM
The latest version of 𝙙𝙤𝙥𝙚𝙙 (and 𝑺𝒉𝒂𝒌𝒆𝑵𝑩𝒓𝒆𝒂𝒌), our defect modelling python packages, have been released!
Incl:
- Major efficiency updates
- Advanced defect/carrier thermodynamics w/custom constraints
- Auto shallow defect handling
- CC diagram generation
...🧵👇
Incl:
- Major efficiency updates
- Advanced defect/carrier thermodynamics w/custom constraints
- Auto shallow defect handling
- CC diagram generation
...🧵👇
Check out our recent work wherein we demonstrate the first monolithic selenium/silicon tandem device, published in PRX Energy!
doi.org/10.1103/PRXE...
doi.org/10.1103/PRXE...
Monolithic Selenium/Silicon Tandem Solar Cells
Experiment and device simulation are combined to explore a monolithically integrated selenium/silicon tandem solar cell, offering insights toward positioning tandem solar cells as strong contenders fo...
doi.org
January 19, 2025 at 7:24 AM
Check out our recent work wherein we demonstrate the first monolithic selenium/silicon tandem device, published in PRX Energy!
doi.org/10.1103/PRXE...
doi.org/10.1103/PRXE...