Large‐Area Tunable Visible‐to‐Near‐Infrared Luminescent Solar Concentrators

Abstract

pushed the efficiency of crystalline silicon (c-Si) PV cells to values approaching the theoretical limit of ≈33%. [3,4] One way to increase the efficiency of PV cells beyond this limit is through the use of luminescent solar concentrators (LSCs) that are devices comprising a transparent matrix embedding optically active centers that absorb the incident radiation, which is re-emitted at a specific wavelength and transferred by total internal reflection to PV cells located at the edges of the matrix. [5,6] Major advances on the LSCs' research can be found in recent reviews. [7][8][9][10][11][12][13] Nowadays, c-Si PV cells are the leader technology in the PV market presenting the higher performance in the nearinfrared (NIR) spectral region (from about 700 to 1100 nm), and, thus, NIR-emitting LSCs resonant with the maximum optical response of c-Si PV cells are looked for to maximize the device performance. Several examples pointed out the potential of NIR-emitting quantum dots (QDs), [14][15][16][17][18] but experimental results demonstrating its use in LSCs can only be found in a few reports. [2,[19][20][21][22][23][24] The maximum reported optical conversion efficiency (η opt ) value is 12.6%, considering all the edges of a planar LSC with PbS QDs. [20] Hexanuclear metal halide clusters [22] and a cyanine derivative [23] with emission in the NIR spectral range were also demonstrated to be suitable for LSCs, although no η opt values were presented. Very recently, some of us reported Luminescent solar concentrators (LSCs) appear as an intriguing way to cope with the limitation of the mismatch between the photovoltaic (PV) cells response and the solar spectrum, with the additional advantage of facilitating urban integration of photovoltaics. A new LSCs geometry based on triangular hollow-core plastic optical fibers (POFs) filled with organic-inorganic hybrid materials doped with Rhodamine 6G, Rhodamine 800, or an Europiumβ-diketonate complex is presented. Large-area LSCs are built from POFs bundle structures, whose assembling is favored by the fiber triangular cross section that also maximizes the coverage of a PV cell surface compared with cylindrical POFs. Each bundle fiber behaves as an individual LSC absorbing UV/blue components of the solar spectrum and emitting visible/NIR radiation. The LSCs are characterized by optical conversion efficiency values up to η opt ≈5.3%, among the largest values reported for single-layer LSCs. Moreover, the coupling between the LSCs to commercial Si PV cells yields maximum power conversion efficiency values of PCE ≈0.74%. The individual waveguiding features of each fiber in the bundle contribute to reduce the reabsorption, as lower performance values (η opt ≈1.5%; PCE ≈0.09%) are estimated for a planar LSC with analogous surface collection area and lightharvesting absorbance.

Lanthanide-based downshifting layers tested in a solar car race

“…The emission properties of the LDS coatings were further quantified through the measurement of the absolute Φ values, with maxima for dU6-Tb of 0.55±0.06 (350 nm) and 0.56±0.06 (320 nm) for tU5-Eu. The values found for the Eu 3+ -based organic-inorganic hybrid materials are of the same order of magnitude of the ones previously reported [27][28][29] , being remarkable the value here reported for dU6-Tb, higher than the 0.25 and 0.32 values found for Ln 3+ coordination polymers doped with Tb 3+ 37 and that of bipyridine-based bridged silsesquioxanes and d-U(600) organic-inorganic hybrids containing Tb 3+ with maximum absolute Φ values of 0.12±0.01 38 and 0.11±0.01 39 , respectively.…”

“…Moreover, after incorporation into the hybrid host, the water molecules coordinated to the Eu 3+ ions will be replaced by the oxygen atoms from the carbonyl groups of the urea cross linkages contributing to suppress the Eu 3+ emission quenching. In addition, this complex incorporated into hybrid matrices was already used for photovoltaic applications as optically active layers in LSCs [27][28][29] . The precursor t-UPTES(5000) was prepared according to the literature 30 and the synthesis of the Eu(tta) 3 ·2H 2 O complex is fully described elsewhere (ESI for details) 26,29 .…”

Luminescent Solar Concentrators Based on Energy Transfer from an Aggregation-Induced Emitter Conjugated Polymer

“…11 Moreover, they can be easily fabricated into various shapes through a sol–gel process, making them compatible with a variety of architectural designs. 43,44…”

Influence of Solar Concentrator in the Form of Luminescent PMMA on the Performance of a Silicon Cell

“…The literature says that the additional increase is around 4.5%. This value is even higher in real conditions, according to the experiment which tested a multi-cylindrical bundle and a layered planar LSC; the value for optical concentration for the bundle was around 5.28%, which is 3.5 times higher than the results shown by planar LSC (1.54%) [34].…”