Display paper briefing, 20 to 27 September

From September 20 to 27, 1,220 papers published in 28 major journals were checked and narrowed to 119 with a display connection, of which 15 are briefly introduced here. Two more are covered as separate in-depth articles. This window brought together the process of making pixels and the problems that show up when pixels are made smaller.

From Sunday, September 20 to Sunday, September 27, 2026, 1,220 papers published in 28 major journals were checked and narrowed to 119 with a display connection. Two of those — a reversible photopatterning method for quantum dots and a liquid-crystal gel temperature sensor — are covered as separate in-depth articles, and 15 are introduced briefly here.

This window brought together processes for making pixels and problems that appear when pixels are made smaller. Two papers on patterning quantum dots with light arrived the same week (item 1 and the in-depth article), and two more on the size effect in micro-LEDs did as well (item 2 and the in-depth article).

Alongside them came work on stretching and making screens see-through (items 3 and 4) and holography (items 9 and 10).

1. Quantum-dot pixels patterned at 12,700 PPI with a 3 mJ/cm² exposure dose

Laser & Photonics Reviews · 09.24 · Zhong Chen, Beijing Jiaotong University, and 7 others

Directly photopatterning quantum dots depends on how well the crosslinker absorbs light, which sets the required exposure dose. A large dose means the ultraviolet light damages the quantum dots.

The team extended the crosslinker’s π-conjugation to raise the molar absorption coefficient above 60,000 L/mol·cm. As a result, they patterned red, green and blue pixels at 12,700 PPI resolution in air with a low exposure dose of 3 mJ/cm².

Device efficiency reached 20.79% for red, 15.27% for green and 3.99% for blue. The low blue figure remains an open problem for this approach. Its method differs from this week’s in-depth article on reversible photopatterning, but the two aim at the same spot.

2. Micro-LEDs with a stepwise aluminum composition in the quantum barrier

Optics Express · 09.23 · Yaozong Zhang, Xiamen University, China, and 9 others

Micro-LEDs lose efficiency as more current flows through them (efficiency droop), and this tendency worsens as the chip gets smaller. One cause is electrons leaking past the quantum well.

The team designed the aluminum composition of the barrier between wells in a stepwise profile, raising the effective barrier height. Charge stays confined inside the well longer.

As a result, external quantum efficiency reached 1.2 times that of the conventional device even at a high current density of 1,000 A/cm², and the efficiency drop that occurs when chip size is cut from 60 to 30 micrometers was also eased.

3. A stretchable OLED screen that keeps a 75% fill factor

Advanced Functional Materials · 09.21 · Young Hyun Son, School of Electrical Engineering, Korea Advanced Institute of Science and Technology (KAIST)

Stretchable screens usually place the light-emitting islands and the wiring that connects them on the same plane. Making more room to stretch then shrinks the area left for pixels.

The team split the light-emitting pixels and the wiring into entirely separate layers. Strain concentrates in the wiring layer and the soft elastomer, and less of it reaches the rigid emitting islands.

They achieved an area fill factor of about 75% together with over 50% uniaxial stretchability, and when the panel was stretched 20%, the strain on the emitting islands stayed below 1.5%. A 3×3 passive-matrix array lit up evenly even under biaxial strain of 30%.

4. A skin-like transparent OLED that clears 80% transmittance

Advanced Functional Materials · 09.22 · Chuang Xue, Jilin Normal University, China, and 9 others

OLEDs that are transparent, flexible and efficient all at once have been held back by electrode materials. Making an electrode transparent lowers its conductivity, and raising conductivity blocks light.

Using a multilayer composite electrode, the team matched the transmittance of the anode and cathode to 87.5% and 88.3%, respectively, at 550 nm. Overall device transmittance reached 80.7%, which the paper describes as the first case of a skin-like transparent OLED clearing 80%.

Efficiency came along with it: a maximum current efficiency of 87.2 cd/A and an external quantum efficiency of 24.9%. Light emits symmetrically from both sides, and a damage-free transfer method made large-area fabrication possible.

5. A ligand that extends the lifetime of cadmium-free red quantum-dot devices

Advanced Optical Materials · 09.21 · Minhyung Lee, Department of Electrical and Computer Engineering, Seoul National University, and 11 others

Indium phosphide (InP) quantum dots are a cadmium-free alternative, but surface defects and an imbalance in charge injection shorten their lifetime.

The team replaced part of the surface ligand with a carbazole-bearing phosphonic-acid molecule (2PACz). It attaches to under-coordinated sites to reduce defects, while also adjusting energy levels so that holes are injected more readily and electrons less so.

In an inverted red device, they obtained a maximum external quantum efficiency of 23.7% and a half-lifetime of 217.8 hours at 1,000 nits. That lifetime figure is extrapolated.

6. An efficiency record for a tin-perovskite LED

Advanced Materials · 09.25 · Zeyu Miao, Jilin University, China, and 10 others

Replacing lead with tin in a perovskite is a path toward non-toxicity, but the lattice is soft and the surface changes easily, so defects form quickly.

The team used a passivation molecule that subtly changes shape to stay attached as the surface changes. Unlike conventional molecules that lock rigidly into one position, it is described as continuing to track the surface even as the lattice shifts.

The CsSnBr3 device produced a peak luminance of 1,344 cd/m² and an external quantum efficiency of 2.64%. That is still far from lead-based devices (over 20%), but it is a record among tin-based ones.

7. A cholesteric liquid crystal producing red, green and blue in a single layer

ACS Applied Materials & Interfaces · 09.23 · Xiujuan Li, University of Science and Technology Beijing, and 4 others

In cholesteric liquid crystals, the pitch of the helix sets the reflected color. They are used in reflective displays that hold color without power, but making full color required stacking multiple layers or repeating alignment steps.

The team used a laser to selectively etch the polymer, creating reservoirs that let chiral molecules seep out at each location. As the molecules diffuse, the helical pitch comes out different at each spot.

As a result, red, green and blue reflective regions formed within a single layer, and the team even demonstrated a full-color reflective prototype with independently driven pixels.

8. A glasses-free 3D micro-LED that collects light with an added metasurface

Optics Express · 09.21 · Jing Bian, Nanjing University of Science and Technology, and 7 others

Glasses-free 3D requires sending a different image to each eye, but light from a micro-LED spreads widely and leaks into neighboring pixels. That narrows the viewing angle and cuts resolution.

The team built a cavity with mirrors above and below to collect the light, then added a continuous metasurface on top that shifts phase across the full 0-to-2π range.

At 465 nm, efficiency was 70.5% when bending light by 10 degrees and 32.7% at 40 degrees. These are simulation-stage results, and bending in two directions at once was also demonstrated.

9. A holographic display designed together with the optics all the way to the eye

Nature Communications · 09.24 · Yongdong Wang, Beijing Institute of Technology, and 4 others

Holographic display research has mostly focused on how to form the image floating in space. The eyepiece optics that the light actually passes through were designed separately, leaving chromatic aberration and distortion behind.

The team proposed a framework that optimizes everything from the light source to the retina at once. It jointly computes the hologram, the eyepiece lens and component placement across multiple wavelengths and depths.

They built two prototypes: a near-eye display with full color, a large depth of field and a wide field of view, and a multifocal freeform AR near-eye display.

10. 3D holography that turns crosstalk between layers into signal

Nature Photonics · 09.23 · Jiaan Gan, Jiangnan University, China, and 5 others

Three-dimensional holograms are usually built by stacking multiple planes at different depths. If the planes are spaced apart, the 3D image looks discontinuous; packed close together, the layers interfere and produce crosstalk.

The team proposed a method that reuses the light passing through the front plane as the input for the next plane. In effect, light that would otherwise be wasted as crosstalk is redirected into signal.

The computational load was handled with a physics-based neural network that needs no pretraining. The approach targets a seamlessly continuous 3D image.

11. An oxide-transistor compact model with a neural network attached

Applied Physics Letters · 09.22 · Mingyu Zhuang, Shandong University, China, and 6 others

Designing a circuit requires a compact model that summarizes a transistor in a single set of equations. For oxide transistors, defects and contact resistance keep those equations from fitting well.

The team left the current equation as is and had only the mobility and threshold voltage produced by a neural network as functions of bias. It is a compromise that stops short of replacing the whole model with a neural network.

Mean absolute error came to 0.56% and 0.36% for n-type IGZO and p-type tin-oxide devices, respectively, and the team ported the model into a circuit-simulator library to model a complementary inverter.

12. Watching IGZO in real time during annealing

Applied Physics Letters · 09.21 · Junghoon Yang, Semiconductor and Display Metrology Group, Korea Research Institute of Standards and Science, and 5 others

The properties of an IGZO thin film are set by annealing, but studies usually compare only before and after treatment. What happens in between stays invisible.

The team used spectroscopic ellipsometry to continuously measure the dielectric function, optical bandgap and Urbach energy throughout a 300°C anneal. By using the difference between the heating and cooling histories, they separated changes that reverse from ones that remain.

IGZO on silicon nitride and IGZO on silicon oxide took different paths under the same conditions. Yet their end states came out nearly identical. That means a before-and-after comparison alone would not reveal this difference.

13. An InP quantum-dot device that tunes electron injection pixel by pixel

Advanced Functional Materials · 09.20 · Jaebum Jeong, Department of Semiconductor Engineering, Gyeongsang National University, and 7 others

Inverted InP quantum-dot devices printed by inkjet suffer from too many electrons being injected. The shallow work function of the oxide used as the electron transport layer breaks the charge balance, charge builds up at the interface, and efficiency drops off at high brightness.

The team inkjet-printed a self-assembled monolayer only at the pixel locations. A phosphonic-acid molecule (ODPA) is selectively deposited on the zinc magnesium oxide electron transport layer to create an interfacial dipole.

The surface work function rose by about 0.08 eV, reducing the excess electron injection, and efficiency and roll-off improved while the turn-on voltage stayed the same. It was applied pixel by pixel on a 200-ppi pixel substrate.

14. A 3D liquid-crystal photonic crystal shifted over 400 nm with light alone

Advanced Functional Materials · 09.20 · Yan-Rong Jiang, Department of Photonics, National Cheng Kung University, Taiwan, and 6 others

The blue phase of a liquid crystal forms a self-assembled 3D lattice with a nanometer-scale period. That means there is no need to separately etch a 3D photonic crystal, but once formed, its wavelength had been hard to shift.

The team added a chiral molecular motor that changes shape under light. When illuminated, the molecule loses its twist and the lattice swells symmetrically, pushing the reflected wavelength further out.

The shift exceeded 400 nanometers, spanning from visible light into the near-infrared, and it was continuous with no phase jumps along the way. It runs on weak light, generating less heat, and exposure patterning also made it possible to create different structures at different locations.

15. Micro-LED sidewall strain relaxation measured by capacitance

Applied Physics Letters · 09.25 · Yoon-Taek Oh, Department of Photonics and Optoelectronics, Hanyang University ERICA · Korea Institute of Energy Technology, and 6 others

When a micro-LED is plasma-etched to shape its pixels, the crystal’s compressive strain relaxes near the sidewalls. As that strain relaxes, the piezoelectric field inside the quantum well weakens, making the sidewall region behave differently from the device’s interior.

The team measured capacitance-voltage curves for five devices with mesa sizes of 20, 40, 60, 80 and 100 micrometers, and used the fact that the intercept differed by size (2.69 to 4.20 V). Smaller devices have a larger share of relaxed edge area, so their average piezoelectric field is lower.

Working backward from this, the relaxation width came out to about 3 micrometers from the sidewall, with a piezoelectric-field difference between the interior and edge of about 0.02 MV/cm. Raman mapping gave the same answer at 0.019 MV/cm. Together with paper 2, these are the two papers in this window that address the size effect in micro-LEDs.