Coming up

12
Oct

Student seminars

Academic or specialist Seminar
12.10.2023 16:00 - 17:00
+ Mixed

Functional layered hybrid materials for photovoltaics
Weifan Luo, Smart Energy Materials, AMI

While the power conversion efficiency of organo-halide perovskite solar cells (PSCs) has soared to over 25%, their prospects for commercialization remain challenged by issues related to stability when exposed to external stimuli. In this study, we have introduced an innovative approach involving the incorporation of a photochromic compound spiro-indoline naphthoxazine (SINO), into the interfacial layer of these PSCs. Our investigation systematically documents the isomerization phenomenon within the perovskite films, employing various characterization techniques. SINO plays a dual role within this context: firstly, it functions as a passivation layer on the perovskite surface, effectively mitigating the undesirable migration of ions. Secondly, SINO's isomerization process positively influences the perovskite material's energy alignment. This effect enhances both power conversion efficiency (PCE) and the real-world stability of solar cells, not only in laboratory-scale configurations but also in larger, more practical modules. The results underscore the promising potential of this approach in advancing the practical application of PSCs.

Reversible covalent bonds for improving single protein characterization in nanopores
Yuanjie Li, BioPhysics, AMI

Single-molecule level characterization of individual proteins by solid-state nanopores has shown substantial promise. Fast translocation time through the nanopore and bandwidth limitations of the instrument make it challenging to characterize the size and shape of individual proteins accurately. In this work we coated the walls of solid state nanopores with a polymer (PAcrAm-g-PEG) that minimizes non-specific interactions with proteins while exposing azide groups. Reaction of these azide groups via a DBCO-activated linker with a phenylboronic acid group (PBA) makes it possible to trap glycated proteins by taking advantage of reversible covalent bond formation between PBA and vicinal diols of glycated amino acid residues in proteins. Dwell time analysis revealed two populations of resistive pulses: Short-lived signals from free translocations (< 0.5 ms) and long-lived signals (0.5 ms – 2 s) from transient covalent bonds between glycated proteins and PBA. Control experiments using nanopores coated with PAcrAm-g-PEG but without PBA groups or with unglycated proteins confirmed that the long dwell time events only occur in the presence of both glycated proteins and PBA groups. Variations in the applied potential difference or the pH value of the recording buffer demonstrate the ability to control the trapping time during protein translocation through nanopore. Using covalent trapping of proteins, we determine the approximate size and shape of proteins with an approximately 15 % improvement in accuracy compared to free translocation. This approach, hence, selectively extends the residence time of natively glycated proteins (or of proteins that are intentionally modified with chemical groups that bear vicinal diols) thereby providing selectivity and improving the accuracy of single-molecule level protein characterization.


When? 12.10.2023 16:00 - 17:00
Online Meeting ID: 860 2124 5073 Passcode: 234055

 Online event link

Where? PER 18 Auditorium
Chemin des Verdiers 4
1700 Fribourg
speaker Weifan Luo, Smart Energy Materials, AMI

Yuanjie Li, BioPhysics, AMI
Contact Adolphe Merkle Institute
Jessica Clough
jessica.clough@unifr.ch
Chemin des Verdiers 4
1700 Fribourg
+41 26 300 9254 4
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