Molecular solar thermal energy storage in Dewar Pyrimidone beyond 1.6 MJ/kg
Data files
Feb 06, 2026 version files 6.21 MB
-
1_UV-Vis_P1-to-P4_310nm.csv
686.35 KB
-
10_DSC_D1-to-D4.csv
1.92 MB
-
11_TGA_P1-to-P4.csv
629.64 KB
-
12_Energy-density-of-MOST_MJoverkg.csv
448 B
-
13_IR-study_expt1-to-expt5.csv
82.49 KB
-
2_UV-Vis_P-4_thin-film_310nm.csv
36.53 KB
-
3_UV-Vis_D2-to-D4_95C.csv
265.20 KB
-
4_UV-Vis_P-3_Cycling-in-Water.csv
262.60 KB
-
5_Cycling-study_P-3.csv
942 B
-
6_Quantum-yield_P1-to-P4_310nm.csv
18.02 KB
-
7_Thermal-kinetics_D2-to-D4_85C-90C-95C.csv
16.44 KB
-
8_Photoluminescence-study_P-3.csv
351.84 KB
-
9_DSC_P1-to-P4.csv
1.94 MB
-
README.md
5.10 KB
Abstract
Storing sunlight in a compact and rechargeable form remains a central challenge for solar energy utilization. Molecular solar thermal (MOST) energy storage systems, which harness photon energy and release it as heat on demand, provide a direct approach, but have long failed to meet practical benchmarks. Inspired by the architecture of DNA, we report a pyrimidone-based MOST system that stores energy in the strained Dewar photoisomer upon excitation at 300 nm. Designed with sustainability in mind, the system operates solvent-free and remains compatible with aqueous environments while overcoming one of the field’s greatest hurdles: the controlled extraction and transfer of stored heat. When catalyzed by acid, the Dewar isomer releases enough heat to boil water (~0.5 mL). These advances help point the way toward decentralized solar heat storage and off-grid energy solutions.
Dataset DOI: 10.5061/dryad.rxwdbrvqg
Author information
Corresponding author: Grace G. D. Han (grace_han@ucsb.edu)1,2, K. N. Houk (houk@ucla.edu)3
1Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA, 93016 USA.
2Department of Chemistry, Brandeis University, Waltham, MA, 02453 USA.
3Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, 90095-156 USA.
Description of the data and file structure
This supplementary dataset supports our study on a pyrimidone-based molecular solar thermal (MOST) energy storage system. The dataset includes:
- UV–Vis spectroscopy datasets (Files 1–5): solution, thin-film, and cycling studies in DMSO and water
- Photoisomerization quantum yield study (File 6)
- Thermal reversion kinetics study (File 7)
- Photoluminescence study (File 8)
- DSC thermograms of pyrimidones and Dewar isomers (Files 9–10)
- TGA profiles of pyrimidones (File 11)
- Energy density comparison dataset (File 12)
- IR thermal imaging heat-transfer experiments (File 13)
Notes
- Units are included in the headers and/or variable descriptions.
- Experimental details are provided in the associated Main Text and Supplementary Materials.
- Some files contain multiple experimental blocks within one CSV file; all column headers are uniquely labeled for repository compatibility.
Files and variables
File: 1_UV-Vis_P1-to-P4_310nm.csv
Description: UV–Vis spectral changes upon photoisomerization of Pyrimidones 1–4 in HPLC-grade acetonitrile under 310 nm irradiation.
Variables:
- wavelength (nm)
- abs (a.u.)
- normalized abs (a.u.)
File: 2_UV-Vis_P-4_thin-film_310nm.csv
Description: UV–Vis absorption spectra from the thin-film irradiation experiment at 310 nm for P-4.
Variables:
- wavelength (nm)
- abs (a.u.)
- normalized abs (a.u.)
File: 3_UV-Vis_D2-to-D4_95C.csv
Description: UV–Vis absorption spectra of Dewars 2–4 in DMSO upon heating at 95 °C.
Variables:
- wavelength (nm)
- abs (a.u.)
- normalized abs (a.u.)
File: 4_UV-Vis_P-3_Cycling-in-Water.csv
Description: UV–Vis cycling study for P-3 in water. P-3 was irradiated to form D-3, then acidified to regenerate pyrimidone in its salt form (P-3+). A second cycle includes neutralization with NaHCO3, irradiation, and re-acidification to reform P-3+.
Variables:
- wavelength (nm)
- abs (a.u.)
- normalized abs (a.u.)
File: 5_Cycling-study_P-3.csv
Description: Multi-cycle reversible isomerization study of D-3 in DMSO induced by thermal treatment and subsequent irradiation.
Variables:
- cycle
- abs (a.u.)
- normalized abs (a.u.)
File: 6_Quantum-yield_P1-to-P4_310nm.csv
Description: Kinetics for the photoisomerization of Pyrimidones 1–4 in degassed HPLC-grade acetonitrile at 293 K under 310 nm irradiation. Absorbance was tracked as a function of time.
Variables:
- time (s)
- abs (a.u.)
File: 7_Thermal-kinetics_D2-to-D4_85C-90C-95C.csv
Description: Thermal reversion kinetics of Dewars 2–4 to Pyrimidones 2–4 in DMSO at 85 °C, 90 °C, and 95 °C. Data were fitted to exponential functions and used for Eyring and Arrhenius analysis.
Variables:
- time (s)
- abs (a.u.)
- 1/T
- R0 = k
- ln(k/T)
- ln(k)
File: 8_Photoluminescence-study_P-3.csv
Description: Absorbance and photoluminescence data for five concentrations of P-3 and the reference dye 2-aminopyridine (2-AP), including acetonitrile emission background.
Variables:
- wavelength (nm)
- abs (a.u.)
- intensity
File: 9_DSC_P1-to-P4.csv
Description: DSC thermograms of Pyrimidones 1–4 measured during heating/cooling cycles (1st heating → 1st cooling → 2nd heating).
Variables:
- temperature (°C)
- heat flow (W/g)
File: 10_DSC_D1-to-D4.csv
Description: DSC thermograms of Dewars 1–4 measured during heating/cooling cycles (1st heating → 1st cooling → 2nd heating).
Variables:
- temperature (°C)
- heat flow (W/g)
File: 11_TGA_P1-to-P4.csv
Description: TGA data for Pyrimidones 1–4.
Variables:
- temperature (°C)
- weight (mg)
- weight (%)
File: 12_Energy-density-of-MOST_MJoverkg.csv
Description: Gravimetric energy densities (MJ/kg) of Dewars 1–4 compared with prior MOST photoswitches, as shown in Fig. 2B. The associated references are provided in the main text.
Variables:
- gravimetric energy density (MJ/kg)
File: 13_IR-study_expt1-to-expt5.csv
Description: Temperature profiles from IR thermal imaging experiments 1–5. Temperatures were extracted from the hottest pixel (hot spot) on the surface of the solution.
Variables:
- time (s)
- temperature (°C)