Donor–Acceptor‐Type Organic‐Small‐Molecule‐Based Solar‐Energy‐Absorbing Material for Highly Efficient Water Evaporation and Thermoelectric Power Generation

Abstract

Recently, owing to the great structural tunability, excellent photothermal property, and strong photobleaching resistance, organic-small-molecule photothermal materials are proposed as promising solar absorbent materials. Herein, through fusing two strong electron-withdrawing units dibenzo[f,h]quinoxaline and anthraquinone units, a rigid planar acceptor dibenzo[a,c]naphtho[2,3-h] phenazine-8,13-dione (PDN) with stronger electron-withdrawing ability is obtained and used to construct donor-acceptor-type organic-small-molecule solar-energyabsorbing material, 2,17-bis(diphenylamino)dibenzo[a,c]naphtho[2,3-h]phenazine-8,13-dione (DDPA-PDN). The new compound exhibits a strong intramolecular charge transfer character and conjugates rigid plane skeleton, endowing it with a broadband optical absorption from 300 to 850 nm in the solid state, favorable photothermal properties, high photothermal conversion ability, and good photobleaching resistance. Under laser irradiation at 655 nm, the solid photothermal conversion efficiency of the resulting DDPA-PDN molecule reaches 56.23%. Additionally, DDPA-PDN-loaded cellulose papers equipped with abundant microchannels for water flow are integrated with thermoelectric devices, thus achieving an evaporation rate and voltage as high as 1.07 kg m −2 h −1 and 83 mV under 1 kW m −2 solar irradiation, respectively. This study demonstrates the application of photothermal organic-small-molecules in water evaporation and power generation, therefore offering a valuable prospect of their utilization in solar energy harvesting.

High-Efficiency Photo-Thermo-Electric System with Waste Heat Utilization and Energy Storage

“…From the above discussion, it is known that each part of PEG@PPy@CF/TEG/CF­(−F) works together to make full use of solar energy, resulting in the solar energy utilization efficiency being as high as 86%, which is much higher than other samples, as shown in Figure i. For this system, the utilization efficiency of solar energy is also higher than that reported by other studies in the photo-thermo-electric field. ,,,, …”

“…At present, there are two main ways to convert solar energy into electrical energy. − One is a photovoltaic technology in which electron–hole pairs can be generated efficiently. − However, the environment was seriously polluted in the fabrication process of photovoltaic devices. The other one is a photo-thermo-electric technology in which solar energy is first converted into heat − and then into electrical energy. − Compared with photovoltaic devices, the fabrication process of photo-thermo-electric devices is cleaner. − …”

Integrating Dual-Interfacial Liquid Metal Based Nanodroplet Architectures and Micro-Nanostructured Engineering for High Efficiency Solar Energy Harvesting

“…More significantly, this value is much higher than most photothermal materials in previously reported cases, for example, LN- (lignin, 22%), GO- (20%), Fe 3 O 4 - (57%), and graphene- (80%) based polymer absorbers. ,, In this category, that is, paper-like photothermal materials, heat radiation loss is considered to be the dominant energy loss in addition to conduction loss. Thus, we calculated the heat radiation loss in the photo-to-heat process . The radiation loss is estimated to be 2.6% for S-PVA/LMP 8 -rGO absorber (Supplementary Note 4), suggesting that most of the solar thermal energy can be sufficiently utilized.…”

“…Thus, we calculated the heat radiation loss in the photo-to-heat process. 62 The radiation loss is estimated to be 2.6% for S-PVA/LMP 8 -rGO absorber (Supplementary Note 4), suggesting that most of the solar thermal energy can be sufficiently utilized.…”

A three-dimensional arched solar evaporator based on hydrophilic photothermal fibers inspired by hair for eliminating salt accumulation with desalination application

“…Currently, research scientists have developed many excellent solar steam generation devices [12][13][14] based on metal-based inorganic materials, [15][16][17][18] carbon-based inorganic materials, [19][20][21][22] organic-inorganic hybrid materials, [23][24][25] polymeric materials, [26][27][28][29] organic co-crystals materials, 30 purely organic smallmolecule materials [31][32][33][34][35] and other photothermal nanomaterials 36,37 as solar heaters, but most of them possess complicated preparation processes and photobleaching problems. More importantly, improving the water evaporation rate is as important as paying attention to the ability of the device to discharge salt in the solar evaporation research concept.…”