a The selective reflection and transmission mechanism of N*-LCs. b The composition of the prepared N*-LCs in this study.

Results

POM images of a R4, b R7 and c R8, d CPL, e DC and f g_lum values of circularly polarized light generated after unpolarized light of different wavelengths passes through R7. g CPL, h DC and i g_lum values of circularly polarized light generated after unpolarized light of different wavelengths passes through S7.

The chiroptical properties and ground-state chirality of the prepared N*-LCs was confirmed through UV-vis and CD spectroscopy, indicating their potential to convert unpolarized light into circularly polarized light. It is well-established that the generation of high dissymmetry factors in CPL from N*-LCs is attributed to their selective reflection and transmission mechanisms. Specifically, when an unpolarized light with a wavelength matching the selective reflection/transmission band of a N*-LC passes through the N*-LC material, it is split into two circularly polarized light with opposite handedness. Among these, the circularly polarized light with the same handedness as the N*-LC is selectively reflected, while the opposite-handed component is transmitted and detected^30,52. Therefore, according to the definition of the dissymmetry factor, g_lum = 2(I_L – I_R)/(I_L + I_R), this mechanism theoretically enables the generation of CP light with g_lum values reaching the theoretical maximum of ±2. To validate this, the reflection and transmission spectra of the prepared N*-LCs and the CPL properties of light transmitted through the N*-LCs at different wavelengths were all systematically measured (Supplementary Tables S3, S4, Supplementary Figs. S6–S27). In terms of spectral peak positions, consistent with the UV-vis and CD spectra, the reflection and transmission peaks of the N*-LCs shift with changes in doping ratio. Moreover, for each specific N*-LC, the spectral peaks in the UV-vis, CD, reflection, and transmission spectra can be directly correlated. CPL measurements show that unpolarized light passing through R-type and S-type N*-LCs generates left-handed and right-handed circularly polarized light, respectively. Furthermore, the CPL results reveal a clear correlation between the wavelength of the incident unpolarized light and the resulting CPL properties. Specifically, when the wavelength of the unpolarized light approaches the reflection/transmission peaks of the N*-LC, the CPL signal and dissymmetry factor increase even reaching the theoretical maximum value of ±2 for circularly polarized light. Conversely, as the wavelength of the unpolarized light moves away from the reflection/transmission peaks, both the CPL signal and dissymmetry factor decrease. For example, the reflection spectrum of R7 exhibits a peak around 560 nm. Therefore, when an unpolarized light with a wavelength near 560 nm passes through R7 via its selective reflection-transmission mechanism, left-handed circularly polarized light with a dissymmetry factor of 2 can be obtained. As the wavelength of the non-polarized light deviates from 560 nm, with the DC intensity remaining constant, both the CPL signal intensity and the g_lum value gradually decrease. At unpolarized light wavelengths of 520 nm and 600 nm, the g_lum value decrease to 1.7 and 1.6, respectively (Fig. 2d–f, Supplementary Fig. S16). Similarly, for S7, its reflection spectrum shows a peak around 520 nm. Consequently, when 520 nm unpolarized light passes through S7, right-handed circularly polarized light with a dissymmetry factor of -2 is generated. As the wavelength of the light shifts away from 520 nm, the CPL signal and |g_lum| value gradually decrease, with g_lum value reaching −1.7 at 480 nm and 560 nm (Fig. 2g–i, Supplementary Fig. S25). Through this comprehensive series of CPL measurements, demonstrated the potential of these N*-LC to convert unpolarized light into circularly polarized light with high dissymmetry factors.

Circularly polarized luminescence of solution-N*-LC composite system

After confirming that the prepared N*-LCs possess the potential to convert unpolarized light into circularly polarized light with high dissymmetry factors, a general strategy for achieving circularly polarized luminescence with high dissymmetry factors in achiral solutions was proposed. The achiral luminescent molecules are first employed to generate unpolarized light with varying wavelengths in solution. Next, N*-LCs with selective reflection-transmission spectra that match the emission wavelengths of solutions are selected and placed behind the achiral solution. Through the selective reflection and transmission processes of the N*-LCs, the unpolarized light generated by the achiral solution is transformed into circularly polarized light with high dissymmetry factors (Fig. 3). To validate the feasibility of this strategy, 4-methylumbelliferyl phosphate disodium (4-MUP, Fig. 3), an achiral, water-soluble fluorescent substrate for phosphatase detection, was first dissolved in aqueous solution for testing. In aqueous solution, the fluorescence emission spectrum of 4-MUP is shown in Supplementary Fig. S34. Following the strategy proposed in this work, the emission spectrum of 4-MUP in aqueous solution was compared with the reflection spectra of various N*-LCs. The results revealed that the R1 and S1 N*-LCs exhibited the best matching with the emission spectrum (Fig. 4a). Consequently, R1 or S1 was placed behind the 4-MUP aqueous solution, and the CPL performance of the entire composite system was tested. The results fully met expectations, as shown in Fig. 4b, the CPL spectra displayed excellent symmetry after the inclusion of R1 and S1. Moreover, the luminescence dissymmetry factors of circularly polarized light emitted by the composite system reached the theoretical values of +2 and −2, respectively (Supplementary Table S5, entry 1-2; Fig. 4c and Supplementary Fig. S37). With this result, the CPL properties of a series of achiral molecules in aqueous solution, combined with N*-LCs, were tested using this strategy. Including disodium N-(ethoxycarbonylmethyl)-6-methoxyquinolinium bromide (MQAE), 6-methoxy-N-(3-sulfopropyl)quinolinium (SPQ), 4,4’-bis(2-sulfostyryl)biphenyl (CBS), lucifer yellow CH dipotassium salt (LY), rhodamine 6G (R6G), sulforhodamine B (SRB) and rhodamine B (RB), as shown in Fig. 3. The fluorescence emission spectra of these molecules are shown in Supplementary Fig. S34. As examples, Fig. 4a demonstrates the matching of the fluorescence emission peaks of CBS, LY, R6G, RB, and reflection spectra of S-type N*-LC. Therefore, by employing this strategy, Fig. 4b, c illustrates that the CPL generated from these solutions-N*-LCs composite system exhibited excellent mirror symmetry and dissymmetry factors exceeding ±1.5, with some reaching the theoretical maximum of ±2. SPQ, MQAE and SRB exhibited the same results with others (Supplementary Table S5, Supplementary Figs. S37–S39), thereby confirming the feasibility of this strategy.

Fig. 3: Strategy diagram and molecular structure.

Scope of achiral luminescent molecules tested in this study.

Fig. 4: Spectrum of systems.

a Emission spectra of 4-MUP, CBS, LY, R6G, RB and reflection spectra of various N*-LCs. b CPL spectra and c g_lum values of 4-MUP, CBS, LY R6G and RB in aqueous solution with N*-LC. d Emission spectra of CZ-DPS, TBN, TTPA, Rubrene, REP and reflection spectra of various N*-LCs. e CPL spectra and f g_lum values of CZ-DPS, TBN, TTPA, Rubrene and REP in toluene solution with N*-LC. g Fluorescence spectra (Illustration: fluorescence image of white luminescence aqueous solution). h CIE coordinates and i CPL spectra of white luminescence aqueous solution. j Fluorescence spectra (Illustration: fluorescence image of white luminescence organic solution). k CIE coordinates and l CPL spectra of white luminescence aqueous solution.

To verify the universality of this strategy, further investigations were extended to a range of luminescent organic-solvent soluble molecules (Fig. 3). From blue-light to red-light, including fluorescent molecules such as 9,10-bis[N,N-di-(p-tolyl)-amino]anthracene (TTPA), rubrene, and 4-(dicyanomethylene)-2-methyl-6-(4-dimethylaminostyryl)-4H-pyran (DCM); phosphorescent molecules such as Iridium(III) bis(4-(4-tert-butylphenyl) thieno[3,2-c] pyridinato-N,C2’) acetylacetonate (PO-01-TB) and Ir(mphmq)₂tmd (REP); thermally activated delayed fluorescence (TADF) molecules such as 9,9’-(sulfonylbis(4,1-phenylene))bis(9H-carbazole) (Cz-DPS), 9,9’-(sulfonylbis(4,1-phenylene))bis(3,6-di-tert-butyl-9H-carbazole) (tBuCz-DPS), 10,10’-(sulfonylbis(4,1-phenylene))bis(9,9-dimethyl-9,10-dihydroacridine) (DMAC-DPS), 10-(4-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl)-9,9-dimethyl-9,10-dihydroacridine (DMAC-TRZ), and 10-(phenanthridin-6-yl)-10H-phenoxazine (CPT-PXZ); multiple resonance-induced TADF (MR-TADF) molecules such as 2,12-di-tert-butyl-5,9-bis(4-(tert-butyl)phenyl)-5,9-dihydro-5,9-diaza-13b-boranaphtho[3,2,1-de]anthracene (BNC), and DtBuCzB (TBN). Figure 4d–f using Cz-DPS, TBN, TTPA, PO-01-TB and REP as examples, demonstrates the matching of the fluorescence emission spectra of them with the corresponding reflection spectra of the S-type N*-LC. Similarly, by placing the matching N*-LC behind the toluene solution of these molecules, the composite system successfully achieved high-performance circularly polarized luminescence. The CPL spectra exhibited mirror symmetry, with |g_lum| values greater than 1.6, and even reaching the theoretical maximum of 2. Beyond these five examples, other molecules soluble in organic solvents that were selected in this study also demonstrated high-performance CPL when using the same strategy in toluene solution (Supplementary Table S6, Supplementary Figs. S40–S43). These results collectively demonstrate the feasibility, universality, simplicity, and robustness of this strategy for generating CPL with high |g_lum| values in solution. To study the effect of the incorporation of luminescent molecules on N*-LC, Cz-DPS was doped into R1 at three different ratios (1.4 wt%, 1.8 wt%, and 2.2 wt%). As shown in Supplementary Fig. S46, after doping Cz-DPS into R1, the g_lum values decreased from 2.0 (when Cz-DPS was separated from R1, Supplementary Table S6) to 1.3-1.4. This indicates that the doping of luminescent molecules has disrupted the ordered assembly of N*-LC, thereby reducing the g_lum values.

White-light circularly polarized luminescence has recently garnered significant attention from both academia and industry due to its broad application potential in photoelectric devices, optical sensors, information storage and optical anticounterfeiting⁵³. Achieving white-light CPL emission typically requires a mixture of either chiral molecules emitting the three primary colors or two complementary-color chiral molecules^54,55,56,57. In this work, two mixed solutions were successfully constructed using complementary-color emitters, one in aqueous and the other in organic toluene solvents. Specifically, blue-emitting MQAE and yellow-emitting R6G were combined in the aqueous system, while blue-emitting DMAC-DPS and yellow-emitting PO-01-TB were mixed in the organic system. The fluorescence emission spectra of both systems exhibit dual peaks, with the aqueous system emitting at 455 nm and 564 nm (Fig. 4g), and the organic system emitting at 468 nm and 559 nm (Fig. 4j). Their CIE coordinates are (0.31, 0.34) and (0.31, 0.35), respectively (Fig. 4h, k), both falling within the white-light region, thus demonstrating the successful preparation of white-light solutions. Building on the N*-LC strategy proposed in this article, a method to achieve white-light CPL with high g_lum values was designed by placing two N*-LCs, each selectively reflecting blue and yellow wavelengths, behind the white-light solutions. The experimental results confirm this approach. For the aqueous system, white-light CPL was generated with g_lum values reaching +1.9 (R), −1.8 (S) at 455 nm, and +2.0 (R) and −1.9 (S) at 564 nm (Supplementary Table S7, Supplementary Fig. S44). Similarly, for the organic system, g_lum values reached +1.6 (R) and −1.5 (S) at 468 nm, and +1.6 (R) and −1.8 (S) at 559 nm (Table S7, Supplementary Fig. S44). These results further validate the universality and versatility of the N*-LC strategy for achieving high g_lum values circularly polarized light in solution. Moreover, these results also indicate that when achiral luminescent molecules are separated from N*-LCs, the further enhancement of the |g_lum| can be achieved.

Logic gates

One of the key advantages of luminescent solution systems over solid-state systems is their ability to achieve tunable color changes, making them suitable for applications such as probes. For instance, reversible color modulation can be achieved through acid–base regulation. When an appropriate N*-LC is placed behind the achiral solution, the strategy based on the selective reflection-transmission mechanism of the liquid crystal, as proposed in this study, allows acid and base stimuli to function as CPL switches. In this study, a fluorenyl derivative with two isoquinoline substituents, 5,5’-(9,9-dihexyl-9H-fluorene-2,7-diyl)diisoquinoline (F6IQ), was synthesized. As shown in Supplementary Fig. S36, the fluorescence emission of a 300 μL 1 × 10⁻²M toluene solution of F6IQ occurs at 390 nm, exhibiting a blue color. Upon the addition of 50 μL trifluoroacetic acid (TFA), the nitrogen on the isoquinoline group is protonated (Supplementary Figs. S30–S33), causing the fluorescence emission of the F6IQ + TFA system to shift to 550 nm, changing from blue to yellow. Subsequently, the addition of 150 μL triethylamine (Et₃N) to the F6IQ + TFA system results in the fluorescence emission shifting back to 390 nm, restoring the blue color. This demonstrates that the fluorescence of F6IQ exhibits a distinct reversible acid-base response.

As shown in Fig. 5a, b, the CPL signal of F6IQ in toluene was successfully induced by R2 and S2, with a g_lum value of 1.9 and −2.0 at 397 nm (Fig. 5b, c). Upon addition of TFA to the toluene solution, the DC signal shifted from 397 nm to 550 nm (Supplementary Fig. S45), consistent with the fluorescence emission results. However, influenced by the reflection of N*-LC, the CPL signal shifted to 460 nm (Fig. 5b). Without altering the N*-LC, the g_lum value of F6IQ-TFA decreased to 0.5 and −0.5 at 460 nm, 0.03 and −0.06 at 550 nm (Fig. 5d). Compared to the original CPL signal at 397 nm (g_lum = 1.9 and −2.0), it can be concluded that the CPL signal was “turned off” by the acid treatment. Subsequently, upon addition of Et₃N, the fluorescence emission peak returned to its original position at 397 nm, and the CPL signal was restored with an intensity similar to the initial state (g_lum = 2.0 and −1.9, Fig. 5b, c). Based on the CPL switching behavior of F6IQ described above, a molecular logic gate with multi-output capabilities was designed using acid–base regulation of F6IQ and selective reflection-transmission mechanism. To effectively construct the proposed logic circuit, the freshly prepared toluene solution of F6IQ (1 × 10⁻²M, 300 μL) was defined as the initial state of the logic gate. Four inputs were specified: ultraviolet light (330 nm; INPUT 1), N*-LC (R2/S2; INPUT 2), TFA (50 μL; INPUT 3), and Et₃N (150 μL; INPUT 4). The absence or presence of stimuli was assigned as logical inputs “0” and “1” respectively. Outputs O1, O2, and O3 were defined as the presence of fluorescence at 397 nm, fluorescence at 460 nm, and CPL activity, respectively. The absence and presence of a signal were assigned as logical outputs “0” and “1.” For fluorescence signals at 397 nm or 460 nm, the output was defined as “1.” Similarly, the presence of a CPL signal was assigned as “1”. The truth table and schematic diagram of the logic gate are shown in Table 1 and Fig. 5e. For example, when 330 nm excitation (INPUT 1 = 1), placement of N*-LC behind the solution (INPUT 2 = 1), addition of TFA (INPUT 3 = 1), and addition of Et₃N (INPUT 4 = 1) were applied, the resulting output included CPL activity with 397 nm fluorescence. The corresponding outputs for O1–O3 were 1, 0, and 1, respectively. Thus, the designed logic gate operates under various external inputs and outputs multiple types of information in response to stimuli. This model provides an approach for developing optical logic devices.

Fig. 5: Reversible acid-base response and logic gate.

a Schematic diagram of the CPL switch achieved by utilizing the reversible acid-base response of the solution and the selective reflection-transmission mechanism of N*-LC. b CPL spectra of F6IQ, F6IQ + TFA, F6IQ + TFA + Et₃N in toluene with N*-LC R2 and S2. c g_lum value of F6IQ + TFA + Et₃N in toluene with N*-LC R2 and S2. d g_lum value of F6IQ + TFA in toluene with N*-LC R2 and S2. e The schematic diagram of the designed logic gate.

Table 1 Truth table of the designed logic gate