Organic donor:acceptor semiconductor nanoparticles (NPs) formed through the miniemulsion method have been shown to be active photocatalysts. Here, we report photocatalytic hydrogen (H2) evolution under sacrificial conditions with Pt as a cocatalyst by NPs comprising only the nonfullerene acceptor Y6, stabilized by either sodium dodecyl sulfate (SDS) or the thiophene-containing surfactant 2-(3-thienyl)­ethyl­oxy­butyl­sulfonate sodium salt (TEBS). Typically, changes in the photocatalytic activity of donor:acceptor NPs are associated with differences in morphology due to the use of surfactants. However, as these NPs are single component, their photocatalytic activity has a significantly lower dependence on morphology than two-component donor:acceptor NPs. Results from ultrafast transient absorption spectroscopy show a minor difference between the photophysics of the TEBS- and SDS-stabilized Y6 NPs, with free charges present with either surfactant. The similar photophysics suggest that both TEBS- and SDS-stabilized Y6 NPs would be expected to have similar rates of H2 evolution. However, the results from photocatalysis show that Y6 NPs stabilized by TEBS have a H2 evolution rate 21 times higher than that of the SDS-stabilized NPs under broadband solar-like illumination (400–900 nm). Transmission electron microscopy images of the Y6 NPs show effective photodeposition of Pt on the surface of the TEBS-stabilized NPs. In contrast, photodeposition of Pt is inhibited when SDS is used. Furthermore, the ζ potential of the NPs is higher in magnitude when SDS is present. Hence, we hypothesize that SDS forms a dense, insulating layer on the NP surface which hinders the photodeposition of Pt and reduces the rate of H2 evolution. This insulating effect is absent for TEBS-stabilized Y6 NPs, allowing a high rate of H2 evolution. The TEBS-stabilized Y6 NPs have a H2 evolution rate higher than most single-component organic photocatalysts, signaling the potential use of the Y-series acceptors for H2 evolution in Z-scheme photocatalysis.

We report the use of blend nanoparticles (NPs) of the organic semiconductors PM6 and Y6 for the photocatalytic production of hydrogen under sacrificial conditions, with a 2% mass loading of Pt cocatalyst. When prepared using TEBS, a thiophene-containing surfactant, these blend NPs have a desirable intermixed morphology. Under ≈1-sun illumination from 400 to 900 nm, hydrogen is produced at a rate of 8000 ± 400 μmol h–1 g–1. Remarkably, this rate remains high at 5200 ± 300 μmol h–1 g–1 under 650 to 900 nm excitation, where Y6 is exclusively excited, generating free charges by hole transfer from Y6 to PM6. The rate drops to 2400 ± 200 μmol h–1 g–1 under 400 to 600 nm excitation, where PM6 is preferentially excited and free charges are generated through electron transfer. We also show that the external quantum efficiency is wavelength-independent. This work is the first study to show that free charge generation through hole transfer contributes significantly to hydrogen evolution in a donor:acceptor blend.

Membrane proteins are challenging to analyze by native mass spectrometry (MS) as their hydrophobic nature typically requires stabilization in detergent micelles that are removed prior to analysis via collisional activation. There is however a practical limit to the amount of energy which can be applied, which often precludes subsequent characterization by top‐down MS. To overcome this barrier, we have applied a modified Orbitrap Eclipse Tribrid mass spectrometer coupled to an infrared laser within a high‐pressure linear ion trap. We show how tuning the intensity and time of incident photons enables liberation of membrane proteins from detergent micelles. Specifically, we relate the ease of micelle removal to the infrared absorption of detergents in both condensed and gas phases. Top‐down MS via infrared multiphoton dissociation (IRMPD), results in good sequence coverage enabling unambiguous identification of membrane proteins and their complexes. By contrasting and comparing the fragmentation patterns of the ammonia channel with two class A GPCRs, we identify successive cleavage of adjacent amino acids within transmembrane domains. Using gas‐phase molecular dynamics simulations, we show that areas prone to fragmentation maintain aspects of protein structure at increasing temperatures. Altogether, we propose a rationale to explain why and where in the protein fragment ions are generated.

One of the highest performing materials in organic photovoltaics is a blend of the polymer donor PM6 and non-fullerene acceptor (NFA) Y6. We report the use of 1:1 PM6:Y6 blend nanoparticles (NPs) prepared by the miniemulsion method for the photocatalytic production of hydrogen under sacrificial conditions, with a 2% mass loading of Pt co-catalyst. When pre- pared using TEBS, a thiophene-containing surfactant, these blend NPs have a desirable inter- mixed morphology. Under ≈1-sun illumination from 400 to 900 nm, hydrogen is produced at a rate of 8000 ± 400 μmol h−1 g−1, which is among the highest reported for organic photocata- lysts under similar conditions. Remarkably, this rate remains high at 5200 ± 300 μmol h−1 g−1 under 650 −900 nm excitation, where Y6 is exclusively excited, generating free charges by hole transfer from Y6 to PM6. The rate drops to 2400 ± 200 μmol h−1 g−1 at 400 −600 nm excitation, where PM6 is preferentially excited and free charges are generated from the conventional electron transfer mechanism. Additionally, external quantum efficiencies of 0.27 ± 0.08% at 405nm, 0.19 ± 0.04% at 565nm, and 0.22 ± 0.02% at 780nm were measured, indicating that this photocatalyst uses a broad region of solar spectrum to yield hydrogen from excitation of both the donor and the acceptor. Transient absorption spectroscopy results show that both hole transfer and electron transfer occur following the excitation of Y6 and PM6, respectively. This work is the first study to show that free charge generation via hole transfer is the dominant mechanism of hydrogen evolution in a donor:NFA blend. This work also highlights the potential that other donor:NFA blends may have for highly efficient green hydrogen production.

Membrane proteins are challenging to analyze by native mass spectrometry (MS) as their hydrophobic nature typically requires stabilization in detergent micelles that are removed prior to analysis via collisional activation. There is however a practical limit to the amount of energy which can be applied, which often precludes subsequent characterization by top‐down MS. To overcome this barrier, we have applied a modified Orbitrap Eclipse Tribrid mass spectrometer coupled to an infrared laser within a high‐pressure linear ion trap. We show how tuning the intensity and time of incident photons enables liberation of membrane proteins from detergent micelles. Specifically, we relate the ease of micelle removal to the infrared absorption of detergents in both condensed and gas phases. Top‐down MS via infrared multiphoton dissociation (IRMPD), results in good sequence coverage enabling unambiguous identification of membrane proteins and their complexes. By contrasting and comparing the fragmentation patterns of the ammonia channel with two class A GPCRs, we identify successive cleavage of adjacent amino acids within transmembrane domains. Using gas‐phase molecular dynamics simulations, we show that areas prone to fragmentation maintain aspects of protein structure at increasing temperatures. Altogether, we propose a rationale to explain why and where in the protein fragment ions are generated.