Search arXiv⌕ Search
Home/Archive/arXiv

arXiv · 1512.07466

A Silicon-Singlet Fission Parallel Tandem Solar Cell Exceeding 100 % External Quantum Efficiency

Luis M. Pazos·Ju Min Lee·Anton Kirch·Maxim Tabachnyk·Richard H. Friend·Bruno Ehrler
View original source ↗Read source document ↗Export metadata ↓

Abstract

Silicon solar cells dominate the solar cell market with record lab efficiencies reaching almost 26%. However, after 60 years of research, this efficiency saturated close to the theoretical limit for silicon, and radically new approaches are needed to further improve the efficiency. Here we present parallel-connected tandem solar cells based on down-conversion via singlet fission. This design allows raising the theoretical power conversion efficiency limit to 45% with far superior stability under changing sunlight conditions in comparison to traditional series tandems. We experimentally demonstrate a silicon/pentacene parallel tandem solar cell that exceeds 100% external quantum efficiency at the main absorption peak of pentacene, showing efficient photocurrent addition and proving this design as a realistic prospect for real-world applications.

Explore related subjects

cond-mat.other

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Luis M. Pazos, Ju Min Lee, Anton Kirch, Maxim Tabachnyk, Richard H. Friend, Bruno Ehrler. 2015-12-23. A Silicon-Singlet Fission Parallel Tandem Solar Cell Exceeding 100 % External Quantum Efficiency. https://doi.org/10.1021/acsenergylett.6b00678

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2026

Spin-Axis Dynamic Locking

The all-electrical realization of highly spin-polarized currents and their efficient conversion into pure spin currents remains a fundamental challenge in spintronics. Here, we report a spin-axis dynamic locking (SADL) effect in altermagnets that pins the high and dynamically robust spin polarization to the crystalline axes: an in-plane electric field along one principal axis drives a highly spin-up-polarized current, whereas along the orthogonal axis, it generates a symmetry-enforced, equal-magnitude spin-down current. Consequently, applying an electric field diagonally yields a transverse pure spin current, reaching 100% charge-to-spin conversion in the ideal limit. Mechanistically, SADL originates from a spin-split tent-state band structure whose Lifshitz transitions delimit an open-Fermi-line regime. The momentum-separated Fermi lines carry orthogonal nonzero winding vectors, producing a pronounced velocity contrast while suppressing ordinary backscattering to dynamically stabilize the axial spin selectivity. High-throughput first-principles screening confirms SADL in broad materials. Notably, monolayer Cr2WSe4 and synthesized bulk (BaF)2Mn2Se2O exhibit efficiencies close to the ideal limit, paving the way for ultra-low-power, reconfigurable spintronic devices where the spin states are governed solely by electric field orientation.

cond-mat.other↗
arXiv2026

Antisymmetric spontaneous resistivity anisotropy due to hard-axis collapse in polycrystalline Co thin films

We investigate magnetoresistance phenomena associated with the magnetization hard-axis collapse in polycrystalline Co thin films. Transport measurements reveal that, for specific orientations of the applied magnetic field, the system exhibits distinct remanent resistance levels in both the in-plane longitudinal and transverse voltage responses. In particular, the planar Hall resistance shows multiple stable and reproducible levels at room temperature, enabling the identification of at least three remanent states that can be distinguished and used for information storage. These resistance levels originate from non-uniform magnetic configurations stabilized after the application and removal of the external magnetic field in the hard-axis region. Since this phenomenon remains largely unexplored, we present an incipient study addressing its potential implications from an applied-physics perspective. The observation of such behavior in polycrystalline Co thin films grown on Si substrates suggests a simple and low-cost platform for spintronic memory and sensing devices based on the remanent planar Hall effect.

cond-mat.other↗
arXiv2026

Exact Phase-Space Rotation in the Trapped Quantum Calogero Model

We develop a microscopic phase-space description of the quantum Calogero model in the presence of an external harmonic confining potential. Building on the quantum Lax-pair structure, we construct a Hermitian Wigner operator whose expectation value obeys the exact phase-space evolution equation d_t rho + lambda d_x rho - Omega^2 x d_lambda rho = 0 for arbitrary initial states and to all orders in the interaction strength. The resulting dynamics is a rigid rotation in phase space with period 2 pi/Omega, providing a microscopic realization of the isochronous dynamics of the trapped Calogero model. We further show that the moments of the phase-space density form rotating multiplets rather than independent conserved quantities. In particular, within the quadratic sector, the unique conserved combination is proportional to the trapped Hamiltonian, providing a nontrivial consistency check of the construction. In the limit Omega -> 0, the equation reduces to the exact free-streaming equation of the untrapped model.

cond-mat.other↗