European thin film tandem device proficiency test practical outcomes and preliminary results

Within the European FP7 project CHEETAH, a thin film tandem solar cell round robin proficiency test was conducted between 13 testing laboratories, plus the European Solar Test Installation ESTI of the European Commission s Joint Research Centre as reference laboratory. The purpose of this RR was to compare testing facilities and procedures of the involved partners against the reference measurement by ESTI. In total, five cells were measured. Three tandem devices a Si H c Si and a single junction device representing the top a Si H and the bottom c Si cells, respectively, were provided by one partner. All cells with active area of 1 cm2 were mounted in a standardised housing with connection sockets for I V measurements and a Pt 100 temperature sensor. The cells were initially stabilised and calibrated at ESTI and afterwards circulated. The characterisation was done by I V measurements at Standard Test Conditions and EQE measurements. ESTI checked and re calibrated the cells at the end of the RR before and after further stabilization. Here we report on some preliminary I V measurement results. A number of acquired or conversely still necessary improvements are discussed for the organisational point of view along with some measurement requirements that are still missing or that are not sufficient at many participating laboratorie

A European proficiency test on thin-film tandem photovoltaic devices

A round-robin proficiency test (RR PT) on thin-film multi-junction (MJ) photovoltaic (PV) cells was run between 13 laboratories within the European project CHEETAH. Five encapsulated PV cells were circulated to participants for being tested at Standard Test Conditions (STC). Three cells were a-Si/μc-Si tandem PV devices, each of which had a different short-circuit current ratio between the top junction and the bottom one; the remaining two cells were single-junction PV devices made with material representative of the individual junctions in the MJ cells. The RR PT’s main purpose was to assess the capability of the participating laboratories, in terms of employed facilities and procedures, to test MJ PV devices. Therefore, participants were requested to perform STC measurements of all cells according to their own procedure, which might not include external quantum efficiency measurements. The European Solar Test Installation (ESTI) of the Joint Research Centre (JRC) provided the reference calibrations against which the participants’ results are compared. ESTI made also a verification of the cells performance at STC at the end of the RR PT, in order to allow a comparison between the initial stable state at which the cells were calibrated (just before circulation) and the one they had reached at the end of the RR PT. The overall results of the RR PT are here presented and discussed together with some aspects of MJ PV testing that emerged as not adequately applied or largely missing. Their full implementation is expected to improve the consistency of future results.JRC.C.2-Energy Efficiency and Renewable

Cover Image

The cover image is based on the Research Article A European proficiency test on thin‐film tandem photovoltaic devices by Elena Salis et al., https://doi.org/10.1002/pip.3322. The cover image has been prepared in response to an invitation by the journal to compete for the cover of the issue that includes the paper.JRC.C.2-Energy Efficiency and Renewable