Organic Photothermal Cocrystals: Rational Design, Controlled Synthesis, and Advanced Application

Abstract

Organic photothermal cocrystals, integrating the advantages of intrinsic organic cocrystals and the fascinating photothermal conversion ability, hold attracted considerable interest in both basic science and practical applications, involving photoacoustic imaging, seawater desalination, and photothermal therapy, and so on. However, these organic photothermal cocrystals currently suffer individual cases discovered step by step, as well as the deep and systemic investigation in the corresponding photothermal conversion mechanisms is rarely carried out, suggesting a huge challenge for their further developments. Therefore, it is urgently necessary to investigate and explore the rational design and synthesis of high‐performance organic photothermal cocrystals for future applications. This review first and systematically summarizes the organic photothermal cocrystal in terms of molecular classification, the photothermal conversion mechanism, and their corresponding applications. The timely interpretation of the cocrystal photothermal effect will provide broad prospects for the purposeful fabrication of excellent organic photothermal cocrystals toward great efficiency, low cost, and multifunctionality.

Precise Tuning Near‐Infrared Photothermal Conversion of Ternary Cocrystals via Supramolecular Interactions

“…[47] We speculate that the π-π and C-H•••π interactions will affect the looseness of the molecular stacking of the five ternary cocrystals and thus regulate the rotation of -C(C ≡ N) 2 in the acceptor to tune the PTC ability of cocrystals. In order to analyze the influence of π-π and C-H•••π intermolecular interactions of the donor and guest molecules on the PTC performance of the cocrystals, we performed theoretical simulations on the crystal structure of the ternary cocrystals based on electrostatic potential (ESP) and 2D fingerprints in CrystalExplorer 3.1 software [32] to qualitatively observe and compare the distribution of π-π and C-H•••π intermolecular interactions in ternary cocrystals with different guests. [56,57] According to the Hirshfeld surface analysis (Figure S30 promote the nonradiative process of PTC.…”

“…Because the substantial charge transfer (CT) effect of organic cocrystals would effectively reduce the energy gap to achieve a significant redshift absorption and enhance the nonradiative transition rate, it is expected to have tremendous potential in PTC. [31,32] Thus, several organic cocrystals with effective NIR absorption have been developed, showing great potential for NIR PTC. [33] Notably, expanding the absorption of organic photothermal materials into the NIR region is necessary because this region is where biological tissues have maximum transparency, enabling deeper tissue penetration and minimizing damage to healthy tissues during photothermal therapy.…”

A narrow-bandgap photothermal material based on a donor–acceptor structure for the solar–thermal conversion application

“…[11][12][13] Organic materials have received signicant attention from researchers due to a high molar extinction coefficient, a designable structure and easy modication. Currently the common organic photothermal materials mainly involve organic polycyclic p-conjugated molecules, 14,15 organic cocrystal materials, 16,17 charge-transfer complexes, [18][19][20] and organic D-A type materials. [21][22][23] Among them, some also face the shortcomings of poor photostability, photobleaching, restricted absorption wavelength and limited absorption capacity, which lead to low photothermal conversion efficiency.…”

Multifunctional Mn0.5Zn0.5Fe2O4 Nanoparticle/PPy-PEG Structures for Synergistic Photo-Magnetic Hyperthermia Applications

“…Nevertheless, these inorganic materials are nonbiodegradable and tend to persist in the body for extended durations, which has sparked concerns regarding their potential long-term toxicity. Consequently, there is an imminent necessity to develop PTT agents that are nontoxic and exhibit improved biocompatibility, such as organic PTT formulations. ,, Recently, there has been a notable surge in interest regarding the utilization of organic polymer nano light-absorbers as PTT agents. – Among various NIR light-absorbing polymers, PPy has gained significant attention as a biomaterial for tissue engineering and biosensing due to its demonstrated good biocompatibility in numerous in vivo studies. – Nevertheless, additional endeavors are required to advance the development of PPy-based therapeutic nanoagents for combined magnetothermal–photothermal cancer treatment. Ulteriorly, the PPy shell being an organic polymer exhibits the capability to encapsulate the anticancer drug doxorubicin (DOX), enabling synergistic magnetothermal–photothermal and chemotherapy …”